Cancer pain may arise as a result of tumors compressing or spreading to nearby parts of the body; Pain may be caused by treatments and diagnostic procedures, or by skin, nerves, and other changes caused by an imbalance of hormones or an immune response. Most chronic (long-term) pain is caused by disease, and most acute (short-term) pain is caused by treatment or diagnostic procedures. However, radiation therapy, surgery, and chemotherapy may result in pain that persists long after treatment ends.
The presence of pain depends mainly on the location of the cancer and the stage of the disease. At any given stage, about half of people with malignant cancer experience pain, and two-thirds of people with advanced cancer experience pain so severe that it negatively affects their sleep, mood, social relationships, and daily activities.
With good treatment, cancer pain can be eliminated or well controlled in 80% to 90% of cases, but approximately 50% of cancer patients in the developed world receive less than optimal care, and worldwide, approximately 80% of People with cancer receive little or no pain medication. It has also been documented that the treatment of cancer pain in children is substandard.
Guidelines for the use of drugs in the treatment of cancer pain have been published by the World Health Organization (WHO) and others. The health care professional has an ethical obligation to ensure that the patient or patient’s guardian is as well informed about the risks and benefits associated with pain management options as possible. Sometimes, proper treatment of pain can slightly shorten a dying person’s life.
Pain is classified as acute (short-term) or chronic (long-term). Chronic pain may be continuous, sometimes with a sharp spike (attack), or intermittent: periods of pain relief interspersed with periods of pain. Although the pain is well controlled with long-acting drugs or other treatments, occasional severe attacks can be felt. This is called breakthrough pain, and is treated with fast-acting analgesics.
The majority of people with chronic pain notice difficulties with memory and attention. Objective psychological testing found problems with memory, attention, verbal ability, mental flexibility, and thinking speed. Pain is also associated with increased depression, anxiety, fear, and anger.  Persistent pain reduces overall functionality and quality of life, and lowers the morale of the person experiencing the pain and those who care for them.
The intensity of the pain differs from the ailment that results. For example, through psychosurgery and some pharmacological treatments, or by suggestion (as in hypnosis and placebo), it is possible to reduce the agonies and discomfort caused by pain without affecting its intensity.
Sometimes, pain that occurs in one part of the body is felt as if it is coming from another part of the body. This is called transmitted pain.
Pain in cancer can be caused by mechanical (such as pinching) or chemical (such as inflammation) stimulation of the nerve endings of pain signals located in most parts of the body (called nociceptive pain), or it may be caused by a diseased, compressed nerve, or Damaged, in which case it is called neuropathic pain. Neuralgia is often accompanied by other feelings such as pins and needles.
The patient’s description is the best measure of pain. They are usually asked to rate the severity on a scale of 0 to 10 (where 0 is no pain at all and 10 is the worst pain they have ever felt). However, some patients may be unable to give verbal feedback about their pain. In these cases, you must rely on physiological indicators such as facial expressions, body movements, and sounds such as moaning.
Tumor related causes
Tumors cause pain by crushing or penetrating tissue, leading to infection or inflammation, or releasing chemicals that normally make non-painful stimuli painful.
Invasion of the bone by cancer is the most common source of cancer pain. It is usually felt as a tenderness, with persistent pain in the background and cases of exacerbation of pain on its own or by movement, often described as severe. Rib fractures are common in breast, prostate, and other cancers that involve metastases of cancer to the ribs.
The vascular (blood) system can be affected by solid tumors. Between 15 and 25 percent of deep venous thrombosis are caused by cancer (often by a tumor pressing on a vein), and may be the first sign of cancer. It causes swelling and pain in the legs, especially the calf area, and (rarely) the arms. The superior vena cava (a large vein that carries deoxygenated blood flowing to the heart) can be compressed by a tumor, causing superior vena cava syndrome, which can cause chest wall pain, among other symptoms.
When tumors compress, invade, or inflame parts of the nervous system (such as the brain, spinal cord, nerves, ganglia, or plexus), they can cause pain and other symptoms. Although brain tissue does not contain pain sensors, brain tumors can cause pain by pressing on the blood vessels or the membrane covering the brain (meninges), or indirectly by causing fluid buildup (edema) that may It puts pressure on pain-sensitive tissues.
The pain of cancer of organs, such as the stomach or liver (visceral pain), is widespread and difficult to locate, often causing distant, usually superficial, pain. Tumor invasion of soft tissue can cause pain by inflammatory or mechanical stimulation of pain sensors, or by destruction of moving parts such as ligaments, tendons, and skeletal muscles.
The pain caused by cancer within the pelvis varies with the tissue affected. It may appear at the site of the cancer, but it often spreads to the upper thigh, and may spread to the lower back, external genitalia or perineum.
Cancer pain treatment aims to relieve pain with as few adverse effects as possible, allowing the person to have a good quality of life, a functional level, and a relatively painless death. Although 80-90% of cancer pain can be eliminated or well controlled, nearly half of people with cancer suffer from cancer pain in the developed world, and more than 80% of people with cancer receive less than optimal care. ]
Cancer changes over time, and treatment for pain must reflect this. Several different types of treatment may be needed as the disease progresses. Pain therapists should clearly explain to the patient the cause of the pain and the various treatment possibilities, and should consider, in addition to pharmacotherapy, direct treatment of the underlying disease, raising the pain threshold, cutting, destroying or stimulating the pain pathways, and suggesting lifestyle modification. 29] Reducing psychological, social, and spiritual stress is an essential component of effective pain management.
A person whose pain cannot be well controlled should be referred to palliative care, a pain specialist, or a clinic.
Confrontation strategies edit
The way a person responds to pain affects the severity of the pain (moderately), the degree of disability they experience, and the effect the pain has on their quality of life. The strategies people use to cope with cancer pain include enlisting the help of others; continuing to carry out tasks despite the pain; distraction; rethinking bad thoughts that affect adaptation; prayer or other rituals.
Some people with pain tend to focus on exaggerating the meaning of the threat posed by pain, and valuing their ability to deal with pain as poor and weak. This trend is “disastrous.” The few studies conducted to date indicate that catastrophic cancer pain is associated with high levels of pain and psychological distress. People with cancer pain who accept that pain will persist and be able to lead a meaningful life, becoming less likely to develop catastrophic effects and depression in one study. Two studies found that people with cancer pain who had clear goals, motivation, and means to achieve those goals had significantly lower levels of pain, fatigue, and depression.
People with cancer who are confident in their understanding of their condition and treatment, and are confident in their ability to (a) control their symptoms, (b) cooperate successfully with informal caregivers and (c) communicate effectively with health care providers who have the best experience with good outcomes the pain. Therefore clinicians should take steps to encourage and facilitate effective communication, and should consider psychosocial intervention.
Psychosocial interventions affect the amount of pain a patient experiences and the degree to which it interferes with daily life; the American Institute of Medicine and the American Pain Association both support the inclusion of expert, quality-controlled psychosocial care as part of the Treating cancer pain. Psychosocial interventions include education (addressing, inter alia, the correct use of analgesic medications and effective communication with clinicians) and training in coping skills (changing thoughts, emotions, and behaviors through training in skills such as problem-solving, relaxation, distraction, and cognitive reconstruction).  Education may be most beneficial for people with stage I cancer and their caregivers, and training in coping skills may be most beneficial for stage II and III cancers.
A person’s adaptation to cancer is critically dependent on the support of their family and other informal caregivers, but pain can seriously disrupt such interpersonal relationships, so people with cancer and their therapists should consider including family members and other informal caregivers in therapeutic interventions. Psychosocial expert governed by quality.
If the person is not in severe pain, the WHO guidelines recommend that medications be taken orally as soon as pain occurs, and that non-opioid medications such as paracetamol, dipyrone, NSAIDs or COX-2 inhibitors are started.  Then, if the pain is not completely relieved or disease progression requires more aggressive treatment, mild opioids such as codeine, dextropropoxyphene, dihydrocodeine or tramadol are added to the current non-opioid regimen. If this is or becomes insufficient, the mild opioids are replaced with stronger opioids such as morphine, while continuing the non-opioid therapy and gradually increasing the dose of the opioids until the person is no longer in pain or until maximum relief is achieved without intolerable side effects. If the initial presentation is severe cancer pain, this transition should be skipped and strong opioids should be started 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 NSAIDs (a nonsteroidal anti-inflammatory drug) alone or in combination with opioids in the WHO’s three-step scale for cancer pain management and that there is very low-quality evidence However, some people with moderate or severe cancer pain can get significant levels of effective results within a week or two. 
Some authors challenge the validity of the second step (light opioids), pointing to its high toxicity and low efficacy, and arguing that light opioids can be replaced by small doses of strong opioids (with the possibility of tramadol due to its proven efficacy in cancer pain, and its use particularly for neuropathic pain, And its lower sedative properties, and reduced risk of respiratory depression compared to traditional opioids).
More than half of people with advanced cancer and pain require strong opioids, and these drugs in combination with non-opioid pain medications can produce acceptable analgesia in 70-90% of cases. Morphine is effective in relieving cancer pain. Rarely, side effects such as nausea and constipation are severe enough to stop treatment. Cognitive impairment and analgesia usually appear with the initial dose or with a significant increase in the dose of strong opioids, but these effects improve after 1-2 weeks of the steady dose. Antiemetic and laxative therapy should be started simultaneously with strong opioids, to counteract the usual nausea and constipation. Nausea usually goes away after two or three weeks of treatment, but the use of laxatives should be maintained vigorously.
Analgesics should not be taken “on demand” but “around the clock” (every 3-6 hours), so that each dose is taken before the previous dose has expired, in doses sufficient to ensure continuous pain relief. People taking slow-transit biofilm morphine should also be given immediate-transit (“rescue”) morphine, to use as necessary, to treat episodes of pain (breakthrough pain) that are not suppressed by regular medications.
Oral analgesics are the cheapest and simplest way to administer medication. Other routes of administration such as sublingual, topical, transdermal, parenteral, rectal, or spinal administration should be considered if urgently needed, vomiting, impaired swallowing, GI obstruction, or malabsorption or coma. There is weak current evidence of the effectiveness of a fentanyl skin patch in controlling chronic cancer pain, but it may reduce the severity of constipation compared to oral morphine.
Diseases of the liver and kidneys can affect the biological activity of NSAIDs. When people with reduced liver or kidney function are treated with oral opioids, they should be monitored for the possible need for dose reductions, extended dose intervals, or conversion to other opioids or other routes of administration. The benefits of NSAIDs must be weighed against the risks to the gastrointestinal tract, cardiovascular system, and kidneys.
Not all pain responds completely to classic analgesics, and drugs that are not traditionally considered analgesics but reduce pain in some cases, such as steroids or bisphosphonates, can be used in conjunction with analgesics at any stage. Tricyclic antidepressants, Class I antiarrhythmics, or anticonvulsants are the drugs of choice for neuropathic pain. These adjuvants are a common part of palliative care and are used by up to 90 percent of people with cancer as they near death. Many adjuvants carry significant risks and serious complications.