View source for Cancer pain

{{short description|Type of pain}}
'''Pain in cancer''' may arise from a tumor compressing or infiltrating nearby body parts; from treatments and diagnostic procedures; or from skin, nerve and other changes caused by a hormone imbalance or immune response. Most [[Chronic pain|chronic (long-lasting) pain]] is caused by the illness and most acute (short-term) pain is caused by treatment or diagnostic procedures. However, [[radiotherapy]], surgery and [[chemotherapy]] may produce painful conditions that persist long after treatment has ended.

The presence of pain depends mainly on the location of the [[cancer]] and the [[Cancer staging|stage]] of the disease.<ref name="Hanna2013">{{cite book | veditors = Hanna M, Zylicz Z |title=Cancer Pain|pages=vii & 17|date=1 January 2013|publisher=Springer|isbn=978-0-85729-230-8}}</ref> At any given time, about half of all people diagnosed with [[malignant]] cancer are experiencing pain, and two-thirds of those with advanced cancer experience pain of such intensity that it adversely affects their sleep, mood, social relations and activities of daily living.<ref name="Hanna2013"/><ref name = Marcus2011>{{cite journal | vauthors = Marcus DA | title = Epidemiology of cancer pain | journal = Current Pain and Headache Reports | volume = 15 | issue = 4 | pages = 231–234 | date = August 2011 | pmid = 21556709 | doi = 10.1007/s11916-011-0208-0 | s2cid = 11459509 }}</ref><ref name = Gorin>{{cite journal | vauthors = Sheinfeld Gorin S, Krebs P, Badr H, Janke EA, Jim HS, Spring B, Mohr DC, Berendsen MA, Jacobsen PB | display-authors = 6 | title = Meta-analysis of psychosocial interventions to reduce pain in patients with cancer | journal = Journal of Clinical Oncology | volume = 30 | issue = 5 | pages = 539–547 | date = February 2012 | pmid = 22253460 | pmc = 6815997 | doi = 10.1200/JCO.2011.37.0437 }}</ref>

With competent management, cancer pain can be eliminated or well controlled in 80% to 90% of cases, but nearly 50% of cancer patients in the developed world receive less than optimal care. Worldwide, nearly 80% of people with cancer receive little or no pain medication.<ref name=Hanna-Zylicz>{{cite book| vauthors = Hanna M, Zylicz Z | year=2013| chapter=Introduction| veditors = Hanna M, Zylicz Z | title=Cancer pain| publisher=Springer| page=1| isbn=9780857292308| lccn=2013945729}}</ref> [[Pain management in children|Cancer pain in children]] and in people with [[Intellectual disability|intellectual disabilities]] is also reported as being under-treated.<ref>{{cite journal | vauthors = Millard SK, de Knegt NC | title = Cancer Pain in People With Intellectual Disabilities: Systematic Review and Survey of Health Care Professionals | journal = Journal of Pain and Symptom Management | volume = 58 | issue = 6 | pages = 1081–1099.e3 | date = December 2019 | pmid = 31326504 | doi = 10.1016/j.jpainsymman.2019.07.013 | doi-access = free }}</ref>

Guidelines for the use of drugs in the management of cancer pain have been published by the [[World Health Organization]] (WHO) and others.<ref name = WHO_1996/><ref name = guidelines/> Healthcare professionals have an ethical obligation to ensure that, whenever possible, the patient or patient's guardian is well-informed about the risks and benefits associated with their [[pain management]] options. Adequate pain management may sometimes slightly shorten a dying person's life.<ref name = Randall/>
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==Pain==
{{main|Pain}}

Pain is classed as [[Pain#Chronic versus acute|acute]] (short term) or [[Chronic pain|chronic]] (long term).<ref>{{cite book | vauthors = Portenoy RK, Conn M |title=Cancer Pain: Assessment and Management|chapter-url=https://books.google.com/books?id=_OYWqEAiGCQC&pg=PA8|chapter=Cancer pain syndromes| veditors = Bruera ED, Portenoy RK| date=23 June 2003|publisher=Cambridge University Press|isbn=978-0-521-77332-4|page=8}}</ref> Chronic pain may be continuous with occasional sharp rises in intensity (flares), or intermittent: periods of painlessness interspersed with periods of pain. Despite pain being well controlled by long-acting drugs or other treatment, flares may occasionally be felt; this is called breakthrough pain, and is treated with quick-acting analgesics.<ref name = Induru/>

The majority of people with chronic pain notice memory and attention difficulties. Objective psychological testing has found problems with memory, attention, verbal ability, mental flexibility and thinking speed.<ref name = Kreitler&Niv>{{cite journal | journal = Pain: Clinical Updates | volume = XV | issue = 4 | date = July 2007 | url = http://www.iasp-pain.org/AM/AMTemplate.cfm?Section=Clinical_Updates&CONTENTID=15330&SECTION=Clinical_Updates&TEMPLATE=/CM/ContentDisplay.cfm | title = Cognitive impairment in chronic pain | vauthors = Kreitler S, Niv D | access-date = 2019-06-21 | archive-url = https://web.archive.org/web/20131203065734/http://www.iasp-pain.org/AM/AMTemplate.cfm?Section=Clinical_Updates&CONTENTID=15330&SECTION=Clinical_Updates&TEMPLATE=%2FCM%2FContentDisplay.cfm | archive-date = 2013-12-03 }}</ref> Pain is also associated with increased [[Depression (mood)|depression]], anxiety, fear, and anger.<ref name="pmid19146872">{{cite journal | vauthors = Bruehl S, Burns JW, Chung OY, Chont M | title = Pain-related effects of trait anger expression: neural substrates and the role of endogenous opioid mechanisms | journal = Neuroscience and Biobehavioral Reviews | volume = 33 | issue = 3 | pages = 475–491 | date = March 2009 | pmid = 19146872 | pmc = 2756489 | doi = 10.1016/j.neubiorev.2008.12.003 }}</ref> Persistent pain reduces function and overall quality of life, and is demoralizing and debilitating for the person experiencing pain and for those who care for them.<ref name = Induru>{{cite journal | vauthors = Induru RR, Lagman RL | title = Managing cancer pain: frequently asked questions | journal = Cleveland Clinic Journal of Medicine | volume = 78 | issue = 7 | pages = 449–464 | date = July 2011 | pmid = 21724928 | doi = 10.3949/ccjm.78a.10054 | s2cid = 19598761 | doi-access = free }}</ref>

Pain's intensity is distinct from its unpleasantness. For example, it is possible through [[psychosurgery]] and some drug treatments, or by suggestion (as in [[hypnosis]] and [[placebo]]), to reduce or eliminate the unpleasantness of pain without affecting its intensity.<ref name="Melzack_1968">{{cite book | author =  [[Ronald Melzack|Melzack R]] & [[Kenneth L. Casey|Casey KL]] | veditors = Kenshalo DR | title =  The skin senses: Proceedings of the first International Symposium on the Skin Senses, held at the Florida State University in Tallahassee, Florida | publisher = Charles C. Thomas| location =  Springfield| year = 1968| pages = 423–443| chapter = Sensory, motivational and central control determinants of chronic pain: A new conceptual model}}</ref>

Sometimes, pain caused in one part of the body feels like it is coming from another part of the body. This is called [[referred pain]].

Pain in cancer can be produced by mechanical (e.g. pinching) or chemical (e.g. inflammation) stimulation of specialized pain-signalling nerve endings found in most parts of the body (called [[Nociception|nociceptive pain]]), or it may be caused by diseased, damaged or compressed nerves, in which case it is called [[neuropathic pain]]. Neuropathic pain is often accompanied by other feelings such as [[pins and needles]].<ref name=Kurita>{{cite journal | vauthors = Kurita GP, Ulrich A, Jensen TS, Werner MU, Sjøgren P | title = How is neuropathic cancer pain assessed in randomised controlled trials? | journal = Pain | volume = 153 | issue = 1 | pages = 13–17 | date = January 2012 | pmid = 21903329 | doi = 10.1016/j.pain.2011.08.013 | s2cid = 38733839 }}</ref>

The patient's own description is the best measure of pain; they will usually be asked to estimate intensity on a scale of 0–10 (with 0 being no pain and 10 being the worst pain they have ever felt).<ref name = Induru/> Some patients, however, may be unable to give verbal feedback about their pain. In these cases one must rely on physiological indicators such as facial expressions, body movements, and vocalizations such as moaning.<ref name="Fundamentals of nursing">{{Cite book|title=Fundamentals of nursing|others=Potter, Patricia Ann,, Perry, Anne Griffin,, Hall, Amy (Amy M.),, Stockert, Patricia A.|isbn=9780323327404|edition=Ninth|location=St. Louis, Mo.|oclc=944132880|last1 = Potter|first1 = Patricia Ann|date=2016-02-25}}</ref>

==Cause==
{{main|Causes of cancer pain}}
About 75 percent of cancer pain is caused by the illness itself; most of the remainder is caused by diagnostic procedures and treatment.<ref name =Portenoy>{{cite journal | vauthors = Portenoy RK | title = Treatment of cancer pain | journal = Lancet | volume = 377 | issue = 9784 | pages = 2236–2247 | date = June 2011 | pmid = 21704873 | doi = 10.1016/S0140-6736(11)60236-5 | s2cid = 1654015 }}</ref>

===Tumor-related===
Tumors cause pain by crushing or infiltrating tissue, triggering infection or inflammation, or releasing chemicals that make normally non-painful stimuli painful.

Invasion of bone by cancer is the most common source of cancer pain. It is usually felt as tenderness, with constant background pain and instances of spontaneous or movement-related exacerbation, and is frequently described as severe.<ref name = Twycross>{{cite book | vauthors = Twycross R, Bennett M | chapter = Cancer pain syndromes | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | url = https://archive.org/details/clinicalpainmana00syke | url-access = limited | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = [https://archive.org/details/clinicalpainmana00syke/page/n47 27]–37 | year = 2008 }}</ref><ref name = Urch>{{cite book | vauthors = Urch CE, Suzuki R | chapter = Pathophysiology of somatic, visceral, and neuropathic cancer pain | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | url = https://archive.org/details/clinicalpainmana00syke | url-access = limited | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = [https://archive.org/details/clinicalpainmana00syke/page/n23 3]–12 | year = 2008 }}</ref> Rib fractures are common in breast, prostate and other cancers with rib metastases.<ref name= Koh&Portenoy/>

The vascular (blood) system can be affected by solid tumors. Between 15 and 25 percent of [[deep vein thrombosis]] is caused by cancer (often by a tumor compressing a vein), and it may be the first hint that cancer is present. It causes swelling and pain in the legs, especially the calf, and (rarely) in the arms.<ref name= Koh&Portenoy>{{cite book | vauthors = Koh M, Portenoy RK | veditors = Bruera ED, Portenoy RK |title= Cancer Pain Syndromes|year= 2010|publisher= Cambridge University Press|isbn= 9780511640483 |pages=53–85 }}</ref> The [[superior vena cava]] (a large vein carrying circulating, de-oxygenated blood into the heart) may be compressed by a tumor, causing [[superior vena cava syndrome]], which can cause chest wall pain among other symptoms.<ref name= Koh&Portenoy/><ref name="M.D.Ballantyne2010">{{cite book| vauthors = Gundamraj NR, Richmeimer S | veditors = Fishman SM, Ballantyne JC, Rathmell JP |chapter=Chest Wall Pain |title=Bonica's Management of Pain|chapter-url=https://books.google.com/books?id=Pms0hxH8f-sC&pg=PA1045|access-date=10 June 2013|date=January 2010|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-6827-6|pages=1045–}}</ref>

When tumors compress, invade or inflame parts of the nervous system (such as the brain, [[spinal cord]], [[nerve]]s, [[ganglia]] or [[Nerve plexa|plexa]]), they can cause pain and other symptoms.<ref name = Twycross/><ref name = Foley>{{cite book | vauthors = Foley KM | year = 2004 |chapter = Acute and chronic cancer pain syndromes | pages = 298–316 | title = Oxford textbook of palliative medicine | veditors = Doyle D, Hanks G, Cherny N, Calman K | publisher = OUP | location = Oxford | isbn = 0-19-851098-5 }}</ref> Though brain tissue contains no pain sensors, [[brain tumor]]s can cause pain by pressing on blood vessels or the membrane that encapsulates the brain (the [[meninges]]), or indirectly by causing a build-up of fluid ([[edema]]) that may compress pain-sensitive tissue.<ref name = Fitzgibbon_&_Loeser_34>{{harvnb|Fitzgibbon|Loeser|2010|p=34}}</ref>

Pain from cancer of the [[Organ (anatomy)|organs]], such as the stomach or liver ([[visceral pain]]), is diffuse and difficult to locate, and is often [[Referred pain|referred]] to more distant, usually superficial, sites.<ref name = Urch/> Invasion of soft tissue by a tumor can cause pain by inflammatory or mechanical stimulation of pain sensors, or destruction of mobile structures such as ligaments, tendons and skeletal muscles.<ref name = Fitzgibbon_&_Loeser_35>{{harvnb|Fitzgibbon|Loeser|2010|p=35}}</ref>

Pain produced by cancer within the pelvis varies depending on the affected tissue. It may appear at the site of the cancer but it frequently radiates diffusely to the upper thigh, and may [[referred pain|refer]] to the lower back, the external genitalia or [[perineum]].<ref name = Twycross/>

===Diagnostic procedures===
Some diagnostic procedures, such as [[lumbar puncture]] (see [[post-dural-puncture headache]]), [[venipuncture]], [[paracentesis]], and [[thoracentesis]] can be painful.<ref name=IASP>[http://www.iasp-pain.org/AM/Template.cfm?Section=Home&Template=/CM/ContentDisplay.cfm&ContentID=7191 International Association for the Study of Pain] {{webarchive|url=https://web.archive.org/web/20110928121554/http://www.iasp-pain.org/AM/Template.cfm?Section=Home&Template=%2FCM%2FContentDisplay.cfm&ContentID=7191 |date=2011-09-28 }} Treatment-Related Pain</ref>

===Treatment-related===
[[File:Chemotherapy bottles NCI.jpg|thumb|upright|alt=Six medicine bottles.|Chemotherapy drugs]]
Potentially painful cancer treatments include: 
*[[immunotherapy]] which may produce joint or muscle pain; 
*radiotherapy, which can cause skin reactions, [[enteritis]], fibrosis, [[myelopathy]], bone [[necrosis]], [[neuropathy]] or [[plexopathy]]; 
*chemotherapy, often associated with [[chemotherapy induced peripheral neuropathy]], [[mucositis]], [[arthralgia|joint pain]], [[myalgia|muscle pain]], and abdominal pain due to diarrhea or constipation; 
*[[hormone therapy]], which sometimes causes pain flares; 
*[[targeted therapy|targeted therapies]], such as [[trastuzumab]] and [[rituximab]], which can cause muscle, joint or chest pain; 
*[[angiogenesis inhibitor]]s like [[bevacizumab]], known to sometimes cause bone pain; 
*surgery, which may produce post-operative pain, post-amputation pain or pelvic floor [[myalgia]].

===Infection===
The chemical changes associated with infection of a tumor or its surrounding tissue can cause rapidly escalating pain, but infection is sometimes overlooked as a possible cause. One study<ref name = Gonzalez>{{cite journal | vauthors = Gonzalez GR, Foley KM, Portenoy RK | year = 1989 | title = Evaluative skills necessary for a cancer pain consultant | journal = American Pain Society Meeting, Phoenix Arizona}}</ref> found that infection was the cause of pain in four percent of nearly 300 people with cancer who were referred for pain relief. Another report described seven people with cancer, whose previously well-controlled pain escalated significantly over several days. Antibiotic treatment produced pain relief in all of them within three days.<ref name = Twycross/><ref name = Bruera>{{cite journal | vauthors = Bruera E, MacDonald N | title = Intractable pain in patients with advanced head and neck tumors: a possible role of local infection | journal = Cancer Treatment Reports | volume = 70 | issue = 5 | pages = 691–692 | date = May 1986 | pmid = 3708626 }}</ref>

==Management==
Cancer pain treatment aims to relieve pain with minimal adverse treatment effects, allowing the person a good [[quality of life]] and level of function and a relatively painless death.<ref name = Schug/> Though 80–90 percent of cancer pain can be eliminated or well controlled, nearly half of all people with cancer pain in the developed world and more than 80 percent of people with cancer worldwide receive less than optimal care.<ref name = Deandrea>{{cite journal | vauthors = Deandrea S, Montanari M, Moja L, Apolone G | title = Prevalence of undertreatment in cancer pain. A review of published literature | journal = Annals of Oncology | volume = 19 | issue = 12 | pages = 1985–1991 | date = December 2008 | pmid = 18632721 | pmc = 2733110 | doi = 10.1093/annonc/mdn419 }}</ref>

Cancer changes over time, and pain management needs to reflect this. Several different types of treatment may be required as the disease progresses. Pain managers should clearly explain to the patient the cause of the pain and the various treatment possibilities, and should consider, as well as drug therapy, directly modifying the underlying disease, raising the pain threshold, interrupting, destroying or stimulating pain pathways, and suggesting lifestyle modification.<ref name = Schug>{{cite book | vauthors = Schug SA, Auret K | chapter = Clinical pharmacology: Principles of analgesic drug management | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | url = https://archive.org/details/clinicalpainmana00syke | url-access = limited | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = [https://archive.org/details/clinicalpainmana00syke/page/n124 104]–22 | year = 2008 }}</ref> The relief of psychological, social and [[spiritual distress]] is a key element in effective pain management.<ref name = WHO_1996>WHO guidelines:
* {{cite book | author = World Health Organization | title = Cancer pain relief. With a guide to opioid availability | edition = 2 | location = Geneva | publisher = WHO | year = 1996 |isbn = 978-92-4-154482-5 | url = https://books.google.com/books?id=FhaII7PMHZcC}}
* {{cite book | author = World Health Organization | title = Cancer pain relief and palliative care in children | location = Geneva | publisher = WHO | year = 1998 | isbn = 978-92-4-154512-9 | url-access = registration | url = https://archive.org/details/cancerpainrelief0000unse }}</ref>

A person whose pain cannot be well controlled should be referred to a [[palliative care]] or pain management specialist or clinic.<ref name = Induru/>

===Psychological===
====Vulnerabilities====

To attempt psychological treatment for cancer pain, medical staff may seek to understand certain vulnerabilities that might predispose certain patients to mental disorders exacerbated by their diagnosis and the physical pains often associated with it. Oncological research has found a significant interplay between psychological vulnerabilities and physical cancer pain in postoperative cancer patients,  implying that these two factors are uniquely- and yet also simultaneously- a  potential part of the cancer pain experience. Psychological vulnerabilities such as anxiety or depression present in patients before cancer operations correlate with higher pain levels after said operations across several research studies, yet others find that these diagnoses sometimes only emerge after these treatment conditions.<ref name=":0">{{Cite journal |last1=Fernando |first1=Asanga |last2=Tokell |first2=Marisa |last3=Ishak |first3=Yostina |last4=Love |first4=Jenna |last5=Klammer |first5=Matthias |last6=Koh |first6=Mickey |date=July 2023 |title=Mental health needs in cancer – a call for change |journal=Future Healthcare Journal |volume=10 |issue=2 |pages=112–116 |doi=10.7861/fhj.2023-0059 |issn=2514-6645 |pmid=37786642|pmc=10540791 }}</ref><ref name=":1">{{Cite journal |last1=Hinrichs-Rocker |first1=Anke |last2=Schulz |first2=Kerstin |last3=Järvinen |first3=Imke |last4=Lefering |first4=Rolf |last5=Simanski |first5=Christian |last6=Neugebauer |first6=Edmund A.M. |date=August 2009 |title=Psychosocial predictors and correlates for chronic post-surgical pain (CPSP) – A systematic review |url=https://onlinelibrary.wiley.com/doi/10.1016/j.ejpain.2008.07.015 |journal=European Journal of Pain |language=en |volume=13 |issue=7 |pages=719–730 |doi=10.1016/j.ejpain.2008.07.015 |pmid=18952472 |issn=1090-3801}}</ref> Use of antidepressants before cancer diagnosis is also associated with greater chronic pain post operation.<ref name=":1" />

Certain sociodemographic characteristics have also been shown to disproportionately affect the types of people who are more likely to experience mental health issues due to cancer diagnoses. Psycho-oncology researchers repeatedly find that 35-40% of people with cancer have some sort of mental disorder that could be clinically diagnosed,<ref name=":0" /> suggesting that mental health issues often coincide with cancer diagnoses in such a way that psychological pain in itself can be considered a cancer pain. It is well-noted that depression and anxiety are significantly correlated with cancer diagnoses, which are mental health disorders disproportionately experienced by female cancer patients and people who live in rural areas.<ref name=":0" /> Many women with breast cancer who undergo surgical procedures experience chronic breast pain that can last upwards of years, contributing not only to the experience of physical pain but also to decreased mental health and quality of life.<ref>{{Cite journal |last1=Miaskowski |first1=C. |last2=Kober |first2=K. |last3=Langford |first3=D. |last4=Levine |first4=J. |last5=Paul |first5=S. |last6=Cooper |first6=B. |last7=Schmidt |first7=B. |last8=Aouizerat |first8=B. |date=April 2014|title=(208) Persistent breast pain following breast cancer surgery is associated with persistent interference, functional impairments, and sensory loss |journal=The Journal of Pain |volume=15 |issue=4 |pages=S28 |doi=10.1016/j.jpain.2014.01.115 |issn=1526-5900|doi-access=free }}</ref>

====Coping strategies====
The way a person responds to pain affects the intensity of their pain (moderately), the degree of disability they experience, and the impact of pain on their [[quality of life]]. Strategies employed by people to cope with cancer pain include enlisting the help of others; persisting with tasks despite pain; distraction; rethinking maladaptive ideas; and prayer or ritual.<ref name = Porter&Keefe>{{cite journal | vauthors = Porter LS, Keefe FJ | title = Psychosocial issues in cancer pain | journal = Current Pain and Headache Reports | volume = 15 | issue = 4 | pages = 263–270 | date = August 2011 | pmid = 21400251 | doi = 10.1007/s11916-011-0190-6 | s2cid = 37233457 }}</ref>

Some people in pain tend to focus on and exaggerate the pain's threatening meaning, and estimate their own ability to deal with pain as poor. This tendency is termed "catastrophizing".<ref name = Rosenstiel>{{cite journal | vauthors = Rosenstiel AK, Keefe FJ | title = The use of coping strategies in chronic low back pain patients: relationship to patient characteristics and current adjustment | journal = Pain | volume = 17 | issue = 1 | pages = 33–44 | date = September 1983 | pmid = 6226916 | doi = 10.1016/0304-3959(83)90125-2 | s2cid = 21533907 }}</ref> The few studies so far conducted into catastrophizing in cancer pain have suggested that it is associated with higher levels of pain and psychological distress. People with cancer pain who accept that pain will persist and nevertheless are able to engage in a meaningful life were less susceptible to catastrophizing and depression in one study. People with cancer pain who have clear goals, and the motivation and means to achieve those goals, were found in two studies to experience much lower levels of pain, fatigue and depression.<ref name = Porter&Keefe/>

People with cancer who are confident in their understanding of their condition and its treatment, and confident in their ability to (a) control their symptoms, (b) collaborate successfully with their informal carers and (c) communicate effectively with health care providers experience better pain outcomes. Physicians should therefore take steps to encourage and facilitate effective communication, and should consider [[psychosocial]] intervention.<ref name = Porter&Keefe/> Resilience among cancer patients can be promoted by psychological support and provision of illness-related information through patient education. Illness-related information enhances self-management skills and emotional support.<ref>{{Cite journal |last1=Sihvola |first1=Saija Pauliina |last2=Kiwanuka |first2=Frank |last3=Kvist |first3=Tarja Anneli |date=2023-06-01 |title=Promoting resilience among adult cancer patients: An integrative review of patient education methods |url=https://www.sciencedirect.com/science/article/pii/S1462388923000765 |journal=European Journal of Oncology Nursing |volume=64 |pages=102342 |doi=10.1016/j.ejon.2023.102342 |pmid=37290158 |issn=1462-3889}}</ref>

====Psychosocial interventions====
Psychosocial interventions affect the amount of pain experienced and the degree to which it interferes with daily life;<ref name="Gorin"/> and the American [[Institute of Medicine]]<ref name = IOM>{{cite book | vauthors =((Institute of Medicine (US) Committee on Advancing Pain Research, Care, and Education)) | title = Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research | series = The National Academies Collection: Reports funded by National Institutes of Health | publisher = National Academies Press | location = Washington, DC | year = 2011 | pmid = 22553896 | isbn = 9780309214841 | url = https://www.ncbi.nlm.nih.gov/books/NBK91497/ }}</ref> and the [[American Pain Society]]<ref name = APS>{{cite journal | vauthors = Gordon DB, Dahl JL, Miaskowski C, McCarberg B, Todd KH, Paice JA, Lipman AG, Bookbinder M, Sanders SH, Turk DC, Carr DB | display-authors = 6 | title = American pain society recommendations for improving the quality of acute and cancer pain management: American Pain Society Quality of Care Task Force | journal = Archives of Internal Medicine | volume = 165 | issue = 14 | pages = 1574–1580 | date = July 2005 | pmid = 16043674 | doi = 10.1001/archinte.165.14.1574 | url = http://www.iom.edu/reports/2011/Relieving-Pain-in-America-A-Blueprint-for-Transforming-Prevention-Care-Education-Research.aspx | access-date = 2012-06-12 | doi-access =  | archive-url = https://web.archive.org/web/20111005010320/http://www.iom.edu/Reports/2011/Relieving-Pain-in-America-A-Blueprint-for-Transforming-Prevention-Care-Education-Research.aspx | archive-date = 2011-10-05 }}</ref> support the inclusion of expert, quality-controlled psychosocial care as part of cancer pain management. Psychosocial interventions include education (addressing among other things the correct use of analgesic medications and effective communication with clinicians) and coping-skills training (changing thoughts, emotions, and behaviors through training in skills such as problem solving, relaxation, distraction and [[cognitive restructuring]]).<ref name = Gorin/> Education may be more helpful to people with [[Cancer staging|stage I]] cancer and their carers, and coping-skills training may be more helpful at stages II and III.<ref name = Porter&Keefe/>

A person's adjustment to cancer depends vitally on the support of their family and other informal carers, but pain can seriously disrupt such interpersonal relationships, so people with cancer and therapists should consider involving family and other informal carers in expert, quality-controlled psychosocial therapeutic interventions.<ref name = Porter&Keefe/> 

===Medications===
{{See|Analgesic adjuvant}}
The WHO guidelines<ref name = WHO_1996/> recommend prompt oral administration of drugs when pain occurs, starting, if the person is not in severe pain, with non-opioid drugs such as [[paracetamol]], [[dipyrone]], [[non-steroidal anti-inflammatory drug]]s or [[COX-2 inhibitor]]s.<ref name = WHO_1996/> Then, if complete pain relief is not achieved or disease progression necessitates more aggressive treatment, mild opioids such as [[codeine]], [[dextropropoxyphene]], [[dihydrocodeine]] or [[tramadol]] are added to the existing non-opioid regime. If this is or becomes insufficient, mild opioids are replaced by stronger opioids such as morphine, while continuing the non-opioid therapy, escalating opioid dose until the person is painless or the maximum possible relief without intolerable side effects has been achieved. If the initial presentation is severe cancer pain, this stepping process should be skipped and a strong opioid should be started immediately in combination with a non-opioid analgesic.<ref name = Schug/>  However, a 2017 Cochrane Review found that there is no high-quality evidence to support or refute the use of non-steroidal anti-inflammatories ([[Nsaids|NSAIDs]]) alone or in combination with opioids for the three steps of the three-step WHO cancer pain ladder and that there is very low-quality evidence that some people with moderate or severe cancer pain can obtain substantial levels of benefit within one or two weeks.<ref>{{cite journal | vauthors = Derry S, Wiffen PJ, Moore RA, McNicol ED, Bell RF, Carr DB, McIntyre M, Wee B | display-authors = 6 | title = Oral nonsteroidal anti-inflammatory drugs (NSAIDs) for cancer pain in adults | journal = The Cochrane Database of Systematic Reviews | volume = 7 | issue = 2 | pages = CD012638 | date = July 2017 | pmid = 28700091 | pmc = 6369931 | doi = 10.1002/14651858.CD012638.pub2 }}</ref>

Some authors challenge the validity of the second step (mild opioids) and, pointing to their higher toxicity and low efficacy, argue that mild opioids could be replaced by small doses of strong opioids (with the possible exception of tramadol due to its demonstrated efficacy in cancer pain, its specificity for neuropathic pain, and its low sedative properties and reduced potential for respiratory depression in comparison to conventional opioids).<ref name =Schug/>

More than half of people with advanced cancer and pain will need strong opioids, and these in combination with non-opioid pain medicine can produce acceptable analgesia in 70–90 percent of cases. Morphine is effective in relieving cancer pain,<ref name="Morphine for cancer pain 2016" /> although oxycodone shows superior tolerability and analgesic effect, though cost may limit its value in certain healthcare systems.<ref>{{cite journal | vauthors = Caraceni A, Hanks G, Kaasa S, Bennett MI, Brunelli C, Cherny N, Dale O, De Conno F, Fallon M, Hanna M, Haugen DF, Juhl G, King S, Klepstad P, Laugsand EA, Maltoni M, Mercadante S, Nabal M, Pigni A, Radbruch L, Reid C, Sjogren P, Stone PC, Tassinari D, Zeppetella G | display-authors = 6 | title = Use of opioid analgesics in the treatment of cancer pain: evidence-based recommendations from the EAPC | journal = The Lancet. Oncology | volume = 13 | issue = 2 | pages = e58–e68 | date = February 2012 | pmid = 22300860 | doi = 10.1016/S1470-2045(12)70040-2 }}</ref> Side effects of nausea and constipation are rarely severe enough to warrant stopping of treatment.<ref name="Morphine for cancer pain 2016">{{cite journal | vauthors = Wiffen PJ, Wee B, Moore RA | title = Oral morphine for cancer pain | journal = The Cochrane Database of Systematic Reviews | volume = 4 | issue = 3 | pages = CD003868 | date = April 2016 | pmid = 27105021 | pmc = 6540940 | doi = 10.1002/14651858.CD003868.pub4 }}</ref> Sedation and cognitive impairment usually occur with the initial dose or a significant increase in dosage of a strong opioid, but improve after a week or two of consistent dosage. [[Antiemetic]] and [[laxative]] treatment should be commenced concurrently with strong opioids, to counteract the usual nausea and constipation. Nausea normally resolves after two or three weeks of treatment but laxatives will need to be aggressively maintained.<ref name = Schug/> Buprenorphine is another opioid with some evidence of its efficacy but only low quality evidence comparing it to other opioids.<ref>{{cite journal | vauthors = Schmidt-Hansen M, Bromham N, Taubert M, Arnold S, Hilgart JS | title = Buprenorphine for treating cancer pain | journal = The Cochrane Database of Systematic Reviews | issue = 3 | pages = CD009596 | date = March 2015 | volume = 2018 | pmid = 25826743 | pmc = 6513197 | doi = 10.1002/14651858.cd009596.pub4 }}</ref>

Analgesics should not be taken "on demand" but "by the clock" (every 3–6 hours), with each dose delivered before the preceding dose has worn off, in doses sufficiently high to ensure continuous pain relief. People taking slow-release morphine should also be provided with immediate-release ("rescue") morphine to use as necessary, for pain spikes ([[breakthrough pain]]) that are not suppressed by the regular medication.<ref name = Schug/>

Oral analgesia is the cheapest and simplest mode of delivery. Other delivery routes such as [[Sublingual administration|sublingual]], topical, transdermal, [[parenteral]], rectal or spinal should be considered if the need is urgent, or in case of vomiting, impaired swallow, obstruction of the gastrointestinal tract, poor absorption or coma.<ref name = Schug/> Current evidence for the effectiveness of [[fentanyl]] [[transdermal patch]]es in controlling chronic cancer pain is weak, but they may reduce complaints of constipation compared with oral morphine.<ref>{{cite journal | vauthors = Hadley G, Derry S, Moore RA, Wiffen PJ | title = Transdermal fentanyl for cancer pain | journal = The Cochrane Database of Systematic Reviews | volume = 10 | issue = 10 | pages = CD010270 | date = October 2013 | pmid = 24096644 | pmc = 6517042 | doi = 10.1002/14651858.CD010270.pub2 }}</ref>

Liver and kidney disease can affect the biological activity of analgesics. When people with diminishing liver or kidney function are treated with oral opioids they must be monitored for the possible need to reduce dose, extend dosing intervals, or switch to other opioids or other modes of delivery.<ref name = Schug/> The benefit of non-steroidal anti-inflammatory drugs should be weighed against their gastrointestinal, cardiovascular, and renal risks.<ref name =Portenoy/>

Not all pain yields completely to classic analgesics, and drugs that are not traditionally considered analgesics but which reduce pain in some cases, such as [[steroids]] or [[bisphosphonates]], may be employed concurrently with analgesics at any stage. [[Tricyclic antidepressants]], class I [[Antiarrhythmic agent|antiarrhythmics]], or [[anticonvulsants]] are the drugs of choice for neuropathic pain.  Such [[adjuvant]]s are a common part of palliative care and are used by up to 90 percent of people with cancer as they approach death. Many adjuvants carry a significant risk of serious complications.<ref name = Schug/>

Anxiety reduction can reduce the unpleasantness of pain but is least effective for moderate and severe pain.<ref name = Price>{{cite book| vauthors = Price DD, Riley JL, Wade JB | year = 2001 | chapter = Psychophysical approaches to measurement of the dimensions and stages of pain | veditors = Turk DC, Melzack R | title = Handbook of pain assessment | publisher = Guildford Press | location = NY | isbn = 1-57230-488-X | page = 65 }}</ref> Since [[anxiolytic]]s such as [[benzodiazepines]] and major [[tranquilizer]]s add to sedation, they should only be used to address anxiety, depression, disturbed sleep or muscle spasm.<ref name = Schug/>

===Interventional===
{{main|Interventional pain management}}
If the analgesic and adjuvant regimen recommended above does not adequately relieve pain, additional options are available.<ref name = Atallah>{{ cite book | vauthors = Atallah JN | chapter = Management of cancer pain | veditors = Vadivelu N, Urman RD, Hines RL | title = Essentials of pain management | publisher = Springer | location = New York | pages=597–628 | isbn = 978-0-387-87578-1 | doi = 10.1007/978-0-387-87579-8 | year = 2011 }}</ref>

====Radiation====
[[Radiotherapy]] is used when drug treatment is failing to control the pain of a growing tumor, such as in bone metastasis (most commonly), penetration of soft tissue, or compression of sensory nerves. Often, low doses are adequate to produce analgesia, thought to be due to reduction in pressure or, possibly, interference with the tumor's production of pain-promoting chemicals.<ref name = Hoskin>{{cite book | vauthors = Hoskin PJ | chapter = Radiotherapy | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = 251–55 | year = 2008 }}</ref> [[Radiopharmaceutical]]s that target specific tumors have been used to treat the pain of metastatic illnesses. Relief may occur within a week of treatment and may last from two to four months.<ref name = Atallah/>

====Neurolytic block====
{{main|Neurolytic block}}
A [[neurolytic block]] is the deliberate injury of a nerve by the application of chemicals (in which case the procedure is called "[[neurolysis]]") or physical agents such as freezing or heating ("[[neurotomy]]").<ref name="FishmanBallantyne2010">{{cite book| vauthors = Fishman S, Ballantyne J, Rathmell JP |title=Bonica's Management of Pain|url=https://books.google.com/books?id=Pms0hxH8f-sC|access-date=15 August 2013|date=January 2010|publisher=Lippincott Williams & Wilkins|isbn=978-0-7817-6827-6|page=1458}}</ref> These interventions cause degeneration of the nerve's fibers and temporary interference with the transmission of pain signals. In these procedures, the thin protective layer around the nerve fiber, the [[basal lamina]], is preserved so that, as a damaged fiber regrows, it travels within its basal lamina tube and connects with the correct loose end, and function may be restored. Surgically cutting a nerve severs these basal lamina tubes, and without them to channel the regrowing fibers to their lost connections, a painful [[neuroma]] or [[deafferentation pain]] may develop. This is why the neurolytic is preferred over the surgical block.<ref name = Williams>{{cite book | vauthors = Williams JE | chapter = Nerve blocks: Chemical and physical neurolytic agents | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = 225–35 | year = 2008 }}</ref>

A brief "rehearsal" block using local anesthetic should be tried before the actual neurolytic block, to determine efficacy and detect side effects.<ref name = Atallah/> The aim of this treatment is pain elimination, or the reduction of pain to the point where opioids may be effective.<ref name = Atallah/> Though the neurolytic block lacks long-term outcome studies and evidence-based guidelines for its use, for people with progressive cancer and otherwise incurable pain, it can play an essential role.<ref name = Williams/>

====Cutting or destruction of nervous tissue====
[[File:Spinal cord tracts - English.svg| thumb | right |alt=Drawing of cross-section of the spinal cord|Cross-section of the spinal cord showing the [[dorsal column]] and the anterolateral [[spinothalamic tract]]s ]]

Surgical cutting or destruction of [[peripheral nervous system|peripheral]] or [[central nervous system|central]] nervous tissue is now rarely used in the treatment of pain.<ref name = Atallah/> Procedures include neurectomy, cordotomy, dorsal root entry zone lesioning, and cingulotomy.

Cutting through or removal of nerves ([[neurectomy]]) is used in people with cancer pain who have short life expectancy and who are unsuitable for drug therapy due to ineffectiveness or intolerance. Because nerves often carry both sensory and motor fibers, motor impairment is a possible side effect of neurectomy. A common result of this procedure is "deafferentation pain" where, 6–9 months after surgery, pain returns at greater intensity.<ref name = Cosgrove/>

[[Cordotomy]] involves cutting nerve fibers that run up the front/side (anterolateral) quadrant of the spinal cord, carrying heat and pain signals to the brain.

[[Pancoast tumor]] pain has been effectively treated with dorsal root entry zone lesioning (destruction of a region of the spinal cord where peripheral pain signals cross to spinal cord fibers); this is major surgery that carries the risk of significant neurological side effects.

[[Cingulotomy]] involves cutting nerve fibers in the brain. It reduces the unpleasantness of pain (without affecting its intensity), but may have [[cognition|cognitive]] side effects.<ref name = Cosgrove/>

====Hypophysectomy====
[[Hypophysectomy]] is the destruction of the [[pituitary gland]], and has reduced pain in some cases of metastatic breast and prostate cancer pain.<ref name = Cosgrove/>

====Patient-controlled analgesia====
[[File:Gray770-en.svg|thumb|300px|right|alt=Drawing of cross-section of spinal cord|Cross section of the spinal cord showing the subarachnoid cavity, dura mater and spinal nerve roots including the dorsal root [[ganglion]]]]
{{main|Patient-controlled analgesia}}

;Intrathecal pump
{{main|Intrathecal administration}}
:An external or implantable [[intrathecal pump]] infuses a [[local anesthetic]] such as [[bupivacaine]] and/or an [[opioid]] such as [[morphine]] and/or [[ziconotide]] and/or some other nonopioid [[analgesic]] as [[clonidine]] (currently only morphine and ziconotide are the only agents approved by the [[US Food and Drug Administration]] for [[Intrathecal administration|IT]] analgesia) directly into the fluid-filled space (the [[subarachnoid cavity]]) between the [[spinal cord]] and its protective sheath, providing enhanced analgesia with reduced systemic [[side effect]]s. This can reduce the level of pain in otherwise intractable cases.<ref name = Atallah/><ref name = Cosgrove>{{cite book | vauthors = Cosgrove MA, Towns DK, Fanciullo GJ, Kaye AD | chapter = Interventional pain management | pages = [https://archive.org/details/essentialspainma00vadi/page/n261 237]–299 | veditors = Vadivelu N, Urman RD, Hines RL | title = Essentials of pain management | url = https://archive.org/details/essentialspainma00vadi | url-access = limited | publisher = Springer | location = New York | isbn = 978-0-387-87578-1 | doi = 10.1007/978-0-387-87579-8 | year = 2011 }}</ref><ref name = Stearns>{{cite journal | vauthors = Stearns L, Boortz-Marx R, Du Pen S, Friehs G, Gordon M, Halyard M, Herbst L, Kiser J | display-authors = 6 | title = Intrathecal drug delivery for the management of cancer pain: a multidisciplinary consensus of best clinical practices | journal = The Journal of Supportive Oncology | volume = 3 | issue = 6 | pages = 399–408 | year = 2005 | pmid = 16350425 }}</ref>

;Long-term epidural catheter
:The outer layer of the sheath surrounding the spinal cord is called the [[dura mater]]. Between this and the surrounding [[vertebra]]e is the [[epidural space]] filled with connective tissue, fat and blood vessels and crossed by the spinal nerve roots. A [[Epidural|long-term epidural catheter]] may be inserted into this space for three to six months, to deliver anesthetics or analgesics. The line carrying the drug may be threaded under the skin to emerge at the front of the person, a process called "tunneling", recommended with long-term use to reduce the chance of any infection at the exit site reaching the epidural space.<ref name = Atallah/>

====Spinal cord stimulation====
Electrical stimulation of the [[dorsal columns]] of the spinal cord can produce analgesia. First, the leads are implanted, guided by [[fluoroscopy]] and feedback from the patient, and the generator is worn externally for several days to assess efficacy. If pain is reduced by more than half, the therapy is deemed to be suitable. A small pocket is cut into the tissue beneath the skin of the upper buttocks, chest wall or abdomen and the leads are threaded under the skin from the stimulation site to the pocket, where they are attached to the snugly fitting generator.<ref name = Cosgrove/> It seems to be more helpful with neuropathic and [[ischemia|ischemic]] pain than nociceptive pain, but current evidence is too weak to recommend its use in the treatment of cancer pain.<ref name = Johnson>{{ cite book | vauthors = Johnson MI, Oxberry SG, Robb K | chapter = Stimulation-induced analgesia | pages = [https://archive.org/details/clinicalpainmana00syke/page/n255 235]–250 | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | url = https://archive.org/details/clinicalpainmana00syke | url-access = limited | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | year = 2008 }}</ref><ref>{{cite journal | vauthors = Peng L, Min S, Zejun Z, Wei K, Bennett MI | title = Spinal cord stimulation for cancer-related pain in adults | journal = The Cochrane Database of Systematic Reviews | issue = 6 | pages = CD009389 | date = June 2015 | volume = 2019 | pmid = 26121600 | pmc = 6464643 | doi = 10.1002/14651858.CD009389.pub3 }}</ref>

===Complementary and alternative medicine===
Due to the poor quality of most studies of [[complementary and alternative medicine]] in the treatment of cancer pain, it is not possible to recommend integration of these therapies into the management of cancer pain. There is weak evidence for a modest benefit from hypnosis; studies of massage therapy produced mixed results and none found pain relief after 4 weeks; Reiki, and touch therapy results were inconclusive; acupuncture, the most studied such treatment, has demonstrated no benefit as an adjunct analgesic in cancer pain; the evidence for music therapy is equivocal; and some herbal interventions such as PC-SPES, mistletoe, and saw palmetto are known to be toxic to some people with cancer. The most promising evidence, though still weak, is for mind-body interventions such as biofeedback and relaxation techniques.<ref name = Induru/>

===Barriers to treatment===
Despite the publication and ready availability of simple and effective [[evidence-based practice|evidence-based]] pain management guidelines by the [[World Health Organization]] (WHO)<ref name = WHO_1996/> and others,<ref name = guidelines>Other clinical guidelines:
* {{cite web | title=Opioids in palliative care: safe and effective prescribing of strong opioids for pain in palliative care of adults | publisher=National Institute for Health and Clinical Excellence | url=http://publications.nice.org.uk/opioids-in-palliative-care-safe-and-effective-prescribing-of-strong-opioids-for-pain-in-palliative-cg140 | date=May 2012 | access-date=2012-08-24 | archive-url=https://web.archive.org/web/20120703005547/http://publications.nice.org.uk/opioids-in-palliative-care-safe-and-effective-prescribing-of-strong-opioids-for-pain-in-palliative-cg140 | archive-date=2012-07-03 | url-status=dead }}
* {{cite web | title=Consensus statement&nbsp;– Symptom management in cancer: Pain, depression and fatigue | publisher=USA National Institutes of Health | url=http://consensus.nih.gov/2002/2002CancerPainDepressionFatiguesos022html.htm | year=2002 | access-date=2011-08-22 | archive-date=2005-11-08 | archive-url=https://web.archive.org/web/20051108192909/http://consensus.nih.gov/2002/2002CancerPainDepressionFatiguesos022html.htm | url-status=dead }}
* {{cite web | title=Recommendations: morphine and alternative opioids for cancer pain | publisher=European Association for Palliative Care | url=http://www.eapcnet.eu/Themes/Clinical/Publicationsdocuments/EAPCRecommendations/tabid/1499/ctl/Details/ArticleID/139/mid/2812/Morphine-and-alternative-opioids-in-cancer-pain-the-EAPC-recommendations.aspx | year=2001 | access-date=2011-08-22 | archive-url=https://web.archive.org/web/20120330212529/http://www.eapcnet.eu/Themes/Clinical/Publicationsdocuments/EAPCRecommendations/tabid/1499/ctl/Details/ArticleID/139/mid/2812/Morphine-and-alternative-opioids-in-cancer-pain-the-EAPC-recommendations.aspx | archive-date=2012-03-30 | url-status=dead }}
* {{cite web | title=Control of pain in adults with cancer | url=http://www.sign.ac.uk/guidelines/fulltext/106/index.html | publisher=Scottish Intercollegiate Guidelines Network | year=2008 | access-date=2011-08-22 | archive-url=https://web.archive.org/web/20111027214354/http://www.sign.ac.uk/guidelines/fulltext/106/index.html | archive-date=2011-10-27 | url-status=dead }}
* {{cite web | title=Clinical practice guidelines in oncology: adult cancer pain | url=http://www.nccn.org/professionals/physician_gls/pdf/pain.pdf | publisher=USA National Comprehensive Cancer Network | year=2011 | access-date=2011-08-22 }}{{registration required}}</ref>
many medical care providers have a poor understanding of key aspects of pain management, including [[nursing assessment|assessment]], [[dose (biochemistry)|dosing]], [[drug tolerance|tolerance]], [[addiction]], and [[adverse effect|side effects]], and many do not know that pain can be well controlled in most cases.<ref name = Schug/><ref name = Paice/> In Canada, for instance, [[veterinarian]]s get five times more training in pain than do physicians, and three times more training than nurses.<ref name = CPS>{{cite web | title = The problem of pain in Canada | url = http://www.canadianpainsummit2012.ca/en/home/about-the-2012-summit/about.aspx#4 | year = 2012 | access-date = 1 July 2012 | publisher = Canadian Pain Summit | archive-url = https://web.archive.org/web/20120114050307/http://www.canadianpainsummit2012.ca/en/home/about-the-2012-summit/about.aspx#4 | archive-date = 14 January 2012 | url-status = dead }}</ref> Physicians may also undertreat pain out of fear of being audited by a regulatory body.<ref name = Induru/>

Systemic institutional problems in the delivery of pain management include lack of resources for adequate training of physicians, time constraints, failure to refer people for pain management in the clinical setting, inadequate insurance reimbursement for pain management, lack of sufficient stocks of pain medicines in poorer areas, outdated government policies on cancer pain management, and excessively complex or restrictive government and institutional regulations on the prescription, supply, and administration of opioid medications.<ref name = Induru/><ref name = Schug/><ref name = Paice/>

People with cancer may not report pain due to costs of treatment, a belief that pain is inevitable, an aversion to treatment side effects, fear of developing addiction or tolerance, fear of distracting the doctor from treating the illness,<ref name = Paice>{{cite journal | vauthors = Paice JA, Ferrell B | title = The management of cancer pain | journal = CA: A Cancer Journal for Clinicians | volume = 61 | issue = 3 | pages = 157–182 | year = 2011 | pmid = 21543825 | doi = 10.3322/caac.20112 | s2cid = 8989759 | doi-access = free }}</ref> or fear of masking a symptom that is important for monitoring progress of the illness. People may be reluctant to take adequate pain medicine because they are unaware of their [[prognosis]], or may be unwilling to accept their diagnosis.<ref name = Randall>{{cite book | vauthors = Randall F | chapter = Ethical issues in cancer pain management | veditors = Sykes N, Bennett MI, Yuan CS | title = Clinical pain management: Cancer pain | edition = 2nd | isbn = 978-0-340-94007-5 | publisher = Hodder Arnold | location = London | pages = 93–100 | year = 2008 }}</ref> Failure to report pain or misguided reluctance to take pain medicine can be overcome by sensitive coaching.<ref name = Schug/><ref name = Paice/>

==Epidemiology==
Pain is experienced by 53 percent of all people diagnosed with malignant cancer, 59 percent of people receiving anticancer treatment, 64 percent of people with metastatic or advanced-stage disease, and 33 percent of people after completion of curative treatment.<ref name = Beuken>{{cite journal | vauthors = van den Beuken-van Everdingen MH, de Rijke JM, Kessels AG, Schouten HC, van Kleef M, Patijn J | title = Prevalence of pain in patients with cancer: a systematic review of the past 40 years | journal = Annals of Oncology | volume = 18 | issue = 9 | pages = 1437–1449 | date = September 2007 | pmid = 17355955 | doi = 10.1093/annonc/mdm056 | doi-access = free }}</ref> Evidence for prevalence of pain in newly diagnosed cancer is scarce. One study found pain in 38 percent of people who were newly diagnosed, another found 35 percent of such people had experienced pain in the preceding two weeks, while another reported that pain was an early symptom in 18–49 percent of cases. More than one third of people with cancer pain describe the pain as moderate or severe.<ref name = Beuken/>

Primary tumors in the following locations are associated with a relatively high prevalence of pain:<ref name = IASP1>{{cite web | url = http://www.iasp-pain.org/files/Content/ContentFolders/GlobalYearAgainstPain2/CancerPainFactSheets/Epidemiology_Final.pdf | title = Epidemiology of Cancer Pain | author = International Association for the Study of Pain | year = 2009 | access-date = 6 June 2012 | archive-date = 16 May 2015 | archive-url = https://web.archive.org/web/20150516164503/http://iasp-pain.org/files/Content/ContentFolders/GlobalYearAgainstPain2/CancerPainFactSheets/Epidemiology_Final.pdf | url-status = dead }}</ref><ref name= "Bruera&Portenoy">{{cite book | veditors = Bruera ED, Portenoy RK | year=2010 | title=Cancer Pain |url=https://archive.org/details/cancerpainassess00brue_795|url-access=limited|vauthors=Higginson IJ, Murtagh F| chapter=Cancer pain epidemiology|page=[https://archive.org/details/cancerpainassess00brue_795/page/n58 45] | publisher=Cambridge University Press | isbn=978-0-511-64048-3}}</ref>

* [[Head and neck cancer|Head and neck]] (67 to 91 percent)
* [[Prostate cancer|Prostate]] (56 to 94 percent)
* [[Endometrial cancer|Uterus]] (30 to  90 percent)
* [[Urogenital neoplasm|The genitourinary system]] (58 to 90 percent)
* [[Breast cancer|Breast]] (40 to 89 percent)
* [[Pancreatic cancer|Pancreas]] (72 to 85 percent)
* [[Esophageal cancer|Esophagus]] (56 to 94 percent)

All people with advanced [[multiple myeloma]] or advanced [[sarcoma]] are likely to experience pain.<ref name= "Bruera&Portenoy"/>

==Legal and ethical considerations==
The [[International Covenant on Economic, Social and Cultural Rights]] obliges signatory nations to make pain treatment available to those within their borders as a duty under the human [[right to health]]. A failure to take reasonable measures to relieve the suffering of those in pain may be seen as failure to protect against inhumane and degrading treatment under Article 5 of the [[Universal Declaration of Human Rights]].<ref name = PCU>{{cite web | url = http://www.iasp-pain.org/AM/AMTemplate.cfm?Section=HOME&CONTENTID=7636&TEMPLATE=/CM/ContentDisplay.cfm&SECTION=HOME | vauthors = Brennan F, Cousins FJ | date = September 2004 | access-date = 28 June 2012 | title = Pain: Clinical Updates: Pain relief as a human right | archive-url = https://web.archive.org/web/20110822114355/http://www.iasp-pain.org/AM/AMTemplate.cfm?Section=HOME&CONTENTID=7636&TEMPLATE=%2FCM%2FContentDisplay.cfm&SECTION=HOME | archive-date = 22 August 2011 | url-status = dead }}</ref> The right to adequate palliative care has been affirmed by the US Supreme Court in two cases, ''[[Vacco v. Quill]]'' and ''[[Washington v. Glucksberg]]'', which were decided in 1997.<ref name = Lohman>{{cite journal | vauthors = Lohman D, Schleifer R, Amon JJ | title = Access to pain treatment as a human right | journal = BMC Medicine | volume = 8 | pages = 8 | date = January 2010 | pmid = 20089155 | pmc = 2823656 | doi = 10.1186/1741-7015-8-8 | doi-access = free }}</ref> This right has also been confirmed in statutory law, such as in the California Business and Professional Code 22, and in other case law precedents in circuit courts and in other reviewing courts in the US.<ref name = Blinderman>{{cite journal | vauthors = Blinderman CD | title = Do surrogates have a right to refuse pain medications for incompetent patients? | journal = Journal of Pain and Symptom Management | volume = 43 | issue = 2 | pages = 299–305 | date = February 2012 | pmid = 22248789 | doi = 10.1016/j.jpainsymman.2011.09.003 | doi-access = free }}</ref> The 1994 Medical Treatment Act of the [[Australian Capital Territory]] states that a "patient under the care of a health professional has a right to receive relief from pain and suffering to the maximum extent that is reasonable in the circumstances".<ref name = PCU/>

Patients and their guardians must be apprised of any serious risks and the common side effects of pain treatments. What appears to be an obviously acceptable risk or harm to a professional may be unacceptable to the person who has to undertake that risk or experience the side effect. For instance, people who experience pain on movement may be willing to forgo strong opioids in order to enjoy alertness during their painless periods, whereas others would choose around-the-clock sedation so as to remain pain-free. The care provider should not insist on treatment that someone rejects, and must not provide treatment that the provider believes is more harmful or riskier than the possible benefits can justify.<ref name = Randall/>

Some patients – particularly those who are terminally ill – may not wish to be involved in making pain management decisions, and may delegate such choices to their treatment providers. The patient's participation in their treatment is a right, not an obligation, and although reduced involvement may result in less-than-optimal pain management, such choices should be respected.<ref name = Randall/>

As medical professionals become better informed about the interdependent relationship between physical, emotional, social, and spiritual pain, and the demonstrated benefit to physical pain from alleviation of these other forms of suffering, they may be inclined to question the patient and family about interpersonal relationships. Unless the person has asked for such psychosocial intervention – or at least freely consented to such questioning – this would be an ethically unjustifiable intrusion into the patient's personal affairs (analogous to providing drugs without the patient's informed consent).<ref name = Randall/>

The obligation of a professional medical care provider to alleviate suffering may occasionally come into conflict with the obligation to prolong life. If a terminally ill person prefers to be painless, despite a high level of sedation and a risk of shortening their life, they should be provided with their desired pain relief (despite the cost of sedation and a possibly slightly shorter life). Where a person is unable to be involved in this type of decision, the law and the medical profession in the United Kingdom allow the doctor to assume that the person would prefer to be painless, and thus the provider may prescribe and administer adequate analgesia, even if the treatment may slightly hasten death. It is taken that the underlying cause of death in this case is the illness and not the necessary pain management.<ref name = Randall/>

One philosophical justification for this approach is the [[doctrine of double effect]], where to justify an act involving both a good and a bad effect, four conditions are necessary:<ref name="Randall" /><ref name="Sulmasy&Pellegrino">{{cite journal | vauthors = Sulmasy DP, Pellegrino ED | title = The rule of double effect: clearing up the double talk | journal = Archives of Internal Medicine | volume = 159 | issue = 6 | pages = 545–550 | date = March 1999 | pmid = 10090110 | doi = 10.1001/archinte.159.6.545 | s2cid = 30189029 }}</ref>

* the act must be good overall (or at least morally neutral)
* the person acting must intend only the good effect, with the bad effect considered an unwanted side effect
* the bad effect must not be the cause of the good effect
* the good effect must outweigh the bad effect

== References ==
{{reflist|30em}}

== Further reading ==
{{refbegin}}
* {{cite book| vauthors = Fitzgibbon DR, Loeser JD | title = Cancer pain: Assessment, diagnosis and management | year = 2010 | location = Philadelphia | isbn = 978-1-60831-089-0}}
{{refend}}

{{Good article}}

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[[Category:Oncology]]
[[Category:Pain]]