Pain in cancer may arise from tumors that compress or infiltrate adjacent body parts; from treatment and diagnostic procedures; or from skin, nerves and other changes caused by hormonal imbalances or immune responses. Most chronic (long-lasting) pain is caused by disease and most acute (short-term) pain is caused by a treatment or diagnostic procedure. However, radiotherapy, surgery and chemotherapy can produce a painful condition that lasts long after the treatment ends.
The presence of pain mainly depends on the location of the cancer and the stage of the disease. At any given time, about half of all people diagnosed with malignant cancer experience pain, and two thirds of those with advanced cancer experience pain with intensity that greatly affects their sleep, mood, social relations and daily activities.
With competent management, cancer pain can be eliminated or well controlled in 80% to 90% of cases, but nearly 50% of cancer patients in developed countries receive less optimal care. Worldwide, nearly 80% of people with cancer receive little or no painkillers. Cancer pain in children is also reported to be under-treatment.
Guidelines for the use of drugs in the management of cancer pain have been published by the World Health Organization (WHO) and others. Health care professionals have an ethical obligation to ensure that, where possible, patient or patient guardians have good information about the risks and benefits associated with their pain management options. Adequate pain management can sometimes slightly shorten the lives of people who are dying.
Video Cancer pain
Pain
Pain is classified as acute (short-term) or chronic (long-term). Chronic pain may continue with an occasional sharp increase in intensity (flare), or intermittent: periods of discomfort interspersed with periods of pain. Although pain is well controlled by long-acting medications or other treatments, flares can sometimes be felt; this is called breakthrough pain, and is treated with rapid work analgesics.
The majority of people with chronic pain pay attention to memory and attention difficulties. An objective psychological test has found problems with memory, attention, verbal ability, mental flexibility and speed of thinking. Pain is also associated with increased depression, anxiety, fear, and anger. Permanent pain diminishes overall function and quality of life, and lowers mood and paralyzes for people who experience pain and for those who care for it.
The intensity of the pain is different from the discomfort. For example, it is possible through psychosurgery and some drug treatments, or with suggestions (such as in hypnosis and placebo), to reduce or eliminate pain discomfort without affecting its intensity.
Sometimes, the pain caused in one part of the body feels like coming from another part of the body. This is called referred pain.
Pain in cancer can be produced mechanically (eg pinching) or chemistry (eg inflammation) stimulation of the nerve endings-signs of specific pain found in most parts of the body (called nociceptive pain), or possibly caused by disease, damaged or compressed nerves, in this case called neuropathic pain. Neuropathic pain is often accompanied by other feelings such as pins and needles.
The patient's own description is the best measure for pain; they will usually be asked to estimate the intensity on a scale of 0-10 (with 0 without pain and 10 being the worst pain they have ever felt). Some patients, however, may not be able to provide verbal feedback about their pain. In this case you have to rely on physiological indicators such as facial expressions, body movements, and vocalizations such as moans.
Maps Cancer pain
Pathophysiology
Nociceptors are nerve fibers that detect stimuli that potentially cause damage to the body such as extreme heat, pressure, or contact with caustic chemicals. When nociceptors detect a stimulus, the pain path begins. The pain pathway consists of four parts: transduction, transmission, perception, and modulation. Transduction is when the thermal, mechanical, or chemical energy of the pain-causing stimulus is converted into electrical energy so that it can be transmitted through the nervous system. Transmission occurs when energy has been altered and nerve impulses travel along the nerve fibers to the spinal cord and to the brain. The target structure is the thalamus, which acts as a control panel and passes the information to the proper part of the brain. When information reaches the brain, perception occurs. It is a point in the path of pain that the person becomes aware of the pain. Based on information in nerve impulses, the brain is able to identify the location and intensity of the pain and the type of reaction it needs. When the brain reacts it is known as modulation. Muscles contract to withdraw from the source of pain and the brain releases inhibiting chemicals to reduce transmission and provide analgesic relief.
Cause
About 75 percent of cancer pain is caused by the disease itself; most of the rest is due to diagnostic procedures and treatments.
Tumors cause pain by destroying or infiltrating the tissues, triggering infections or inflammation, or releasing chemicals that make the stimulation usually painless.
Bone invasion by cancer is the most common source of cancer pain. It is usually perceived as tenderness, with constant back pain and spontaneous or movement-related exacerbation events, and is often described as severe. Rib fractures are common in breast, prostate and other cancers with rib metastasis.
Blood vessels (blood) can be affected by solid tumors. Between 15 and 25 percent of deep venous thrombosis is caused by cancer (often by tumors suppressing blood vessels), and this may be the first clue that cancer is present. This causes swelling and pain in the legs, especially the calves, and (rarely) in the arms. Superior cava vena (a large vein carrying circulating blood, deoxygenation to the heart) can be compressed by the tumor, leading to superior vena cava syndrome, which can cause chest wall pain among other symptoms.
When tumors condense, attack or inflame parts of the nervous system (such as the brain, spinal cord, nerves, ganglia or plexa), they can cause pain and other symptoms. Although brain tissue contains no pain sensors, brain tumors can cause pain by pressing blood vessels or membranes that wrap the brain (meninges), or indirectly by causing fluid buildup (edema) that can suppress pain-sensitive tissues..
Cancerous pains of organs, such as the stomach or liver (visceral pain), spread and are difficult to find, and often referred to further, usually shallow. Soft tissue invasion by tumors can cause pain by inflammatory stimulation or mechanical pain sensors, or destruction of movable structures such as ligaments, tendons and skeletal muscles.
Pain produced by cancer in the pelvis varies depending on the affected tissue. It may appear at the site of the cancer but often diffuse diffusely into the upper thigh, and may refer to the lower back, external genitalia or perineum.
Diagnostic procedure
Some diagnostic procedures, such as lumbar puncture (see post-dural headache), venipuncture, paracentesis, and thoracentesis can be painful.
Related to care
Potentially painful cancer treatments include:
- an immunotherapy that can 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, joint pain, muscle pain, and abdominal pain due to diarrhea or constipation;
- hormone therapy, which sometimes causes painful flares;
- targeted therapies, such as trastuzumab and rituximab, which can cause muscle, joint or chest pain;
- angiogenesis inhibitors such as bevacizumab, known to occasionally cause bone pain; Operation
- , which can produce post-operative pain, post-amputation pain or myalgias on the pelvic floor.
Infection
Chemical changes associated with tumor infection or surrounding tissue can cause increased pain quickly, but infections are sometimes ignored as a possible cause. One study found that infection was the cause of pain in four percent of nearly 300 people with cancers who were referred for pain relief. Another report described seven people with cancer, whose previously well controlled pain improved significantly for several days. Antibiotic treatments resulted in pain relief to them all within three days.
Management
The treatment of cancer pain aims to relieve pain with adverse treatment effects, allowing the person to have a good quality of life and relatively painless level of function and death. Although 80-90 percent of cancer pain can be eliminated or controlled properly, nearly half of all people with cancer pain in developed countries and more than 80 percent of people with cancer worldwide receive less than optimal treatment.
Cancer changes over time, and pain management needs to reflect this. Different types of treatment may be needed as disease develops. The pain manager should clearly explain to the patient the cause of the pain and the possibilities of treatment, and should consider, as well as drug therapy, directly modify the underlying disease, increase pain threshold, disrupt, destroy or stimulate pain pathways, and suggest lifestyle modifications. Eliminating psychological, social, and spiritual pressures is a key element in effective pain management.
A person whose pain can not be controlled properly should be referred to a palliative care specialist or a specialist or a pain management clinic.
Psychological
Overcome strategy
The way a person responds to pain affects the intensity of their pain (moderately), the level of disability they experience, and the impact of pain on their quality of life. Strategies used by people to cope with cancer pain include asking for help from others; stick with duty despite illness; interference; Rethinking maladaptive ideas; and prayer or ritual.
Some people in pain tend to focus and exaggerate the meaning that threatens pain, and estimate their own ability to handle pain as the poor. This tendency is called "catastrophizing". Some research so far conducted into disasters in cancer pain has suggested that it is associated with higher rates of psychological pain and pressure. People with cancer pain who receive the pain will survive and can somehow engage in a life that is less susceptible to disaster and depression in one study. People with cancer pain who have clear goals, and the motivation and means to achieve those goals, are found in two studies to experience much lower levels of pain, fatigue, and depression.
People with cancer are confident in their understanding of their condition and treatment, and are confident in their ability to (a) control their symptoms, (b) collaborate successfully with their informal caregivers and (c) communicate effectively with the experience of healthcare providers better results pain. Therefore, clinicians should take steps to encourage and facilitate effective communication, and should consider psychosocial interventions.
Psychosocial interventions affect the amount of pain experienced and levels that interfere with daily life; and the American Institute of Medicine and the American Pain Society support expert inclusion, quality-controlled psychosocial care as part of the management of cancer pain. Psychosocial interventions include education (addressing among others the correct use of analgesic drugs and effective communication with physicians) and skills training to cope (changing thoughts, emotions and behavior through skills training such as problem solving, relaxation, attention shifting and cognitive restructuring). Education may be more beneficial for people with stage I and their caregivers, and training in coping skills may be more helpful at stage II and III.
Adjustment of a person to cancer depends largely on family support and other informal caregivers, but pain can interfere with the interpersonal relationship, so people with cancer and therapists should consider involving families and other informal caregivers in qualified and skilled psychosocial therapist interventions.
Drugs
WHO guidelines recommend the rapid administration of oral medication when pain occurs, starting, if the person does not experience 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 requires more aggressive treatment, mild opioids such as codeine, dextropropoxifene, dihidrokodein or tramadol are added to the existing non-opioid regime. If this or is not enough, a mild opioid is replaced with a stronger opioid such as morphine, while continuing non-opioid therapy, increasing the dose of opioids until the person does not feel the pain or the possibility of maximum relief without unbearable side effects has been achieved. If the initial presentation is a severe cancer pain, this stepping process must be bypassed and a strong opioid should be started in combination with a non-opioid analgesic.
Some authors challenge the validity of the second step (mild opioid) and, pointing to its higher toxicity and low efficacy, suggest that mild opioids may be replaced by small doses of strong opioids (with possible tramadol exceptions due to their efficacy in cancer pain, their specificity for pain neuropathic, and low sedative properties and reduce the potential for respiratory depression compared with conventional opioids).
More than half of people with advanced cancer and pain will require a strong opioid, and this in combination with non-opioid pain medication can produce acceptable analgesia in 70-90 percent of cases. The updated Cochrane review in 2016 concluded that morphine is effective in relieving cancer pain. Side effects of nausea and constipation are rarely severe enough to stop treatment. Sedation and cognitive impairment usually occur with an initial dose or a significant increase in a strong dose of opioids, but improves after one week or two consistent doses. Antiemetic and laxative treatment should be started in conjunction with a strong opioid, to fight the usual nausea and constipation. Nausea usually disappears after two or three weeks of treatment, but laxatives need to be aggressively maintained.
Analgesics should not be taken "on request" but "on the hour" (every 3-6 hours), with each dose given before the previous dose has faded, in doses high enough to ensure continuous pain relief. People taking slow-release morphine should also be given with immediate release morphine ("salvage") for use as necessary, for surges of pain (breakthrough pain) not suppressed by ordinary drugs.
Oral analgesia is the cheapest and simplest delivery method. Other delivery routes such as sublingual, topical, transdermal, parenteral, rectal or spinal should be considered if immediate needs, or in cases of vomiting, swallowing disorders, gastrointestinal obstruction, poor absorption or coma. The current evidence for the effectiveness of transdermal fentanyl patches in controlling chronic cancer pain is weak but they can reduce complaints of constipation compared with oral morphine.
Liver and kidney disease can affect analgesic biological activity. When people with reduced liver or kidney function are treated with oral opioids, they should be monitored for possible needs to reduce doses, extend dosing intervals, or switch to other opioids or other delivery modes. The benefits of non-steroidal anti-inflammatory drugs should be weighed against their gastrointestinal, cardiovascular, and kidney risks.
Not all pain produces fully classical analgesics, and drugs that are not traditionally regarded as analgesics but which reduce pain in some cases, such as steroids or bisphosphonates, may be used in conjunction with analgesics at any stage. Tricyclic antidepressants, class I antiarrhythmias, or anticonvulsants are the drug 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 approach death. Many adjuvants carry a significant risk of serious complications.
Anxiety reduction can reduce the discomfort of pain but is least effective for moderate and severe pain. Because anxiolytics such as benzodiazepines and major sedatives add to sedation, they should only be used to treat anxiety, depression, disturbed sleep or muscle spasms.
Interventional
If the above recommended analgesic and adjuvant regimens do not adequately relieve pain, additional options are available.
Radiation
Radiotherapy is used when drug treatment fails to control the pain of growing tumors, such as bone metastysis (most often), soft tissue penetration, or sensory nerve compression. Often, low doses are enough to produce analgesia, presumably caused by a decrease in pressure or, perhaps, a disturbance with the production of a pain-triggering chemical tumor. Radiopharmaceuticals that target specific tumors have been used to treat the pain of metastatic disease. Assistance can occur within one week of treatment and may last from two to four months.
Neurolytic block
The neurolytic block is a deliberate nerve injury by the application of a chemical (in this case a procedure called "neurolysis") or a physical agent such as freezing or heating ("neurotomy"). This intervention causes the degeneration of nerve fibers and temporary disturbance with the transmission of pain signals. In this procedure, a thin protective layer around the nerve fibers, the basal lamina, is preserved so that, as the damaged fibers regenerate, it runs in the basal lamina tube and connects with the correct loose end, and the function can be recovered. Surgically bypassing the lymph nerve tube severs, and without them to channel the fibers to their lost connections, painful neuroma or deafferent pain may develop. This is why neurolytics are preferred over surgical blocks.
A short "exercise" block using local anesthesia should be tried before the actual neurolytic block, to determine efficacy and detect side effects. The goal of this treatment is the elimination of pain, or reduction of pain to the point where the opioid may be effective. Although neurolytic blocks have no long-term outcome studies and evidence-based guidelines for their use, for people with progressive cancers and incurable pain, it can play an important role.
Cut or destroy the neural network
Cutting or destructive surgery of peripheral or central nervous tissue is now rarely used in the treatment of pain. Procedures include neurectomy, cordotomy, lesion entering the dorsal root zone, and cingulotomy.
Cutting through or neuromaking (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 damage is a possible side effect of neurectomy. The general result of this procedure is "deafferent pain" in which, 6-9 months after surgery, the pain returns to greater intensity.
Cordotomy involves the cutting of nerve fibers running the front/side (anterolateral) quadrant of the spinal cord, bringing heat and pain signals to the brain.
Pankoast tumor pain has been effectively treated with dorsal root zone lesions (spinal cord destruction where peripheral pain signals cross over to spinal cord fibers); this is a major surgery that carries a significant risk of neurological side-effects.
Cingulotomy involves cutting nerve fibers in the brain. This reduces the discomfort of pain (without affecting its intensity), but may have cognitive side effects.
Hypophysectomy
Hypophysectomy is the destruction of the pituitary gland, and has reduced pain in some cases of metastatic breast and prostate cancer pain.
Patient-controlled analgesia
- Intrathecal Pump
- An intrathecal pump incorporates an opioid such as morphine directly into a fluid-filled space (subarachnoid cavity) between the spinal cord and its protective sheath, providing enhanced analgesia by reducing systemic side effects. This can reduce the level of pain in cases that are difficult to solve. Anxiolytic or nonopioid analgesics, and local anesthetics can also be infused together with opioids.
- Long-term epidural catheter
- The outer layer of the sheath surrounding the spinal cord is called the dura mater. Between this and the surrounding spine is an epidural space filled with connective tissue, fat and blood vessels and crossed by spinal cord roots. Long-term epidural catheters can be incorporated into this space for three to six months, to provide anesthesia or analgesics. The line carrying this drug may be threaded under the skin to appear in front of the person, a process called "tunneling", recommended with long-term use to reduce the likelihood of any infection at the outlet reaching the epidural space./dd>
Spinal cord stenosis
Electrical stimulation of the spinal cord dorsal columns may produce analgesia. First, the leads are implanted, guided by fluoroscopy and feedback from the patient, and the generator is subjected externally for several days to assess its effectiveness. If the pain is reduced by more than half, therapy is considered appropriate. A small pouch is cut into tissue under the top of the buttocks, chest or abdominal wall and the edges are threaded under the skin from the stimulation site into the pocket, where they attach to the fitting generator. It seems more helpful with neuropathic and ischemic pain than nociceptive pain, but current evidence is too weak to recommend its use in the treatment of cancer pain.
Complementary and alternative medicine
Due to the low quality of most complementary and alternative treatment studies in the treatment of cancer pain, it is not possible to recommend the integration of these therapies into the management of cancer pain. There is weak evidence for the simple benefits of hypnosis; massage therapy studies yield mixed results and no one finds pain relief after 4 weeks; Reiki, and the results of touch therapy can not be inferred; acupuncture, the most studied treatment, has shown no benefit as an additional analgesic in cancer pain; evidence for music therapy is unclear; 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.
Barriers to care
Despite the publication and availability of ready and simple effective evidence-based pain management guidelines by the World Health Organization (WHO) and others, many medical care providers have a poor understanding of key aspects of pain management, including assessment, dose, tolerance, addictions, and side effects, and many do not know that pain can be well controlled in many cases. In Canada, for example, veterinarians get five times more training than doctors, and three times more training than nurses. Doctors may also suffer pain for fear of being audited by the regulatory body.
Systemic institutional issues in the management of pain include lack of resources for adequate physician training, time constraints, failure to refer people to pain management in clinical settings, inadequate insurance reimbursement for pain management, lack of adequate pain medication supply in more communities poor. areas, outdated government policies about cancer pain management, and the overly complex or restrictive government and institutional regulation of prescription, supply, and opioid drug delivery.
People with cancer may not report pain due to medical expenses, belief that pain is unavoidable, aversion to the treatment of side effects, the fear of developing addiction or tolerance, the fear of disturbing the doctor from treating the disease, or afraid of covering up important symptoms to monitor disease progression. People may be reluctant to take adequate pain medication because they do not know their prognosis, or may not accept their diagnosis. Failure to report the pain or unwillingness to take pain medication can be overcome with sensitive training.
Epidemiology
The pain 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 disease, and 33 percent of people after completing curative treatment. Evidence for the prevalence of pain in newly diagnosed cancers is still scarce. One study found pain in 38 percent of newly diagnosed people, others found 35 percent of such people had pain in the previous two weeks, while others reported that pain was the first symptom in 18-49 percent of cases. More than a third of people with cancer pain describe pain as moderate or severe.
Primary tumors at the following sites are associated with a relatively high prevalence of pain:
- Head and neck (67 to 91 percent)
- Prostate (56 to 94 percent)
- Uterus (30 to 90 percent)
- The genitourinary system (58 to 90 percent)
- Breasts (40 to 89 percent)
- Pancreas (72 to 85 percent)
- The esophagus (56 to 94 percent)
All people with multiple multiple myeloma or advanced stage sarcoma tend to experience pain.
Legal and ethical considerations
The International Covenant on Economic, Social and Cultural Rights obliges States parties to provide pain medication to those within their borders as an obligation under human rights for health. Failure to take reasonable steps to alleviate the suffering of the afflicted can be seen as a failure to protect against the inhuman and degrading treatment under Article 5 of the Universal Declaration of Human Rights. 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 was decided in 1997. This right has also been confirmed in law laws, such as in California Business and Professional Code 22, and in other cases legal precedents in circuit court and in other US court reviews. The 1994 Medical Treatment Act of the Australian Capital Territory states that a "patient treated by a health professional has the right to receive relief from pain and suffering to the maximum extent reasonable under the circumstances".
Patients and their carers should be informed of the serious risks and common side effects of pain treatment. What appears to be an acceptable or dangerous risk to a professional may be unacceptable to the person who has to take the risk or experience side effects. For example, people who experience pain in movement may be willing to leave strong opioids to enjoy vigilance during their painless period, while others will choose sedation all the time so that it remains pain-free. The providers of care should not claim treatment that is rejected by a person, and may not provide treatments that are more hazardous or risky than those that may be justifiable.
Some patients - especially those who are severely ill - may not want to be involved in pain management decision making, and may delegate these options to their care providers. Patient participation in care is a right, not an obligation, and although reduced involvement may lead to less optimal management of pain, such choices should be respected.
As medical professionals become better informed about the interdependent relationship between physical, emotional, social, and spiritual pain, and the benefits shown to the physical pain of alleviating other forms of suffering, they may tend to question patients and families about interpersonal relationships. Unless the person has requested such psychosocial intervention - or at least freely agreed to such a question - this would be an ethically unreasonable intrusion into the patient's personal affairs (analogous to providing medication without patient consent).
The obligation of professional medical care providers to reduce suffering can sometimes lead to conflict with the obligation to prolong life. If severely ill people prefer painless, despite high sedation rates and the risk of shortening their lives, they should be given the pain reliever they want (regardless of the cost of sedation and life that may be slightly shorter). Where a person can not engage in this type of decision, the UK medical law and profession allows the physician to assume that the person will choose not to feel ill, and thus the provider may prescribe and administer adequate analgesia, even if treatment can hasten death. It is found that the underlying cause of death in this case is the disease and not the necessary pain management.
One philosophical justification for this approach is the doctrine of double effect, in which to justify actions involving good and bad effects, four conditions are required:
- action must be either overall (or at least morally neutral)
- the person acting will only intend good effect, with adverse effects considered as unwanted side effects
- bad effects should not be the cause of good effects
- Good effects must outweigh the bad effects.
The work cited
- Fitzgibbon, DR; Loeser, JD (2010). Cancer Pain: Assessment, diagnosis and management . Philadelphia. ISBNÃ, 1-60831-089-2.
References
Source of the article : Wikipedia
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