<unk>  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. Though 80–90 percent of<unk>  can be eliminated or well controlled, nearly half of all people with<unk>  in the developed world and more than 80 percent of people with cancer worldwide receive less than optimal care. 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. The relief of psychological, social and spiritual distress is a key element in effective pain management. A person whose pain cannot be well controlled should be referred to a palliative care or pain management specialist or clinic. Psychological 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<unk>  include enlisting the help of others; persisting with tasks despite pain; distraction; rethinking maladaptive ideas; and prayer or ritual. 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". The few studies so far conducted into catastrophizing in<unk>  have suggested that it is associated with higher levels of pain and psychological distress. People with<unk>  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<unk>  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. 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. Psychosocial interventions Psychosocial interventions affect the amount of pain experienced and the degree to which it interferes with daily life; and the American Institute of Medicine and the American Pain Society support the inclusion of expert, quality-controlled psychosocial care as part of<unk>  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). Education may be more helpful to people with stage I cancer and their carers, and coping-skills training may be more helpful at stages II and III. 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. Medications The WHO guidelines 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 drugs or COX-2 inhibitors. 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<unk> , this stepping process should be skipped and a strong opioid should be started immediately in combination with a non-opioid analgesic. 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) alone or in combination with opioids for the three steps of the three-step WHO<unk>  ladder and that there is very low-quality evidence that some people with moderate or severe<unk>  can obtain substantial levels of benefit within one or two weeks. 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<unk> , its specificity for neuropathic pain, and its low sedative properties and reduced potential for respiratory depression in comparison to conventional opioids). 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<unk>  although oxycodone shows superior tolerability and anlgesic effect, though cost may limit its value in certain healthcare systems. Side effects of nausea and constipation are rarely severe enough to warrant stopping of treatment. 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. Buprenorphine is another opioid with some evidence of its efficacy but only low quality evidence comparing it to other opioids. 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. Oral analgesia is the cheapest and simplest mode of delivery. Other delivery routes such as 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. Current evidence for the effectiveness of fentanyl transdermal patches in controlling chronic<unk>  is weak but they may reduce complaints of constipation compared with oral morphine. 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. The benefit of non-steroidal anti-inflammatory drugs should be weighed against their gastrointestinal, cardiovascular, and renal risks. 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 antiarrhythmics, or anticonvulsants are the drugs of choice for neuropathic pain. Such adjuvants 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. Anxiety reduction can reduce the unpleasantness of pain but is least effective for moderate and severe pain. Since anxiolytics such as benzodiazepines and major tranquilizers add to sedation, they should only be used to address anxiety, depression, disturbed sleep or muscle spasm. Interventional If the analgesic and adjuvant regimen recommended above does not adequately relieve pain, additional options are available. 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. Radiopharmaceuticals 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. 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"). 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
Cancer pain
Chronic pain
Cancer signs and symptoms
Cancer syndrome
Chronic wound pain
Psychogenic pain
Visceral pain
Stroke recovery