Cancer pain is the pain arising from the tumor infiltrating or compressing nearby body parts. The pain may also result from the diagnostic procedure, treatment, or from changes caused by immune response of hormonal imbalance. Most of the long-lasting (chronic) cancer pains are caused by the illness while short-term pains are as a result of diagnostic or treatment procedures. In some cases, chemotherapy and radiotherapy might result in painful conditions that will still be experienced long after the end of the treatment procedure.
The experienced pain depends on the stage of the cancer and the location. At any given point about 50% of patients with malignant cancer will be experiencing pain and more than two thirds of patients with advanced cancer will experience intense pain that greatly affects their mood, sleep, social life and daily life activities. With proper management, it is possible to eliminate cancer pain or at least control about 80-90 percent of the cases. Though this is the case, about half of the patients in the developed world get less than optimal care and about 80% of cancer patients in the world will receive little or no medical attention in relation to the pain caused by cancer and related treatment procedures.
There are guidelines published by WHO and other organizations that assist in the use of pain management drugs for cancer patients. Healthcare professions have an obligation to ensure that when possible, the patient’s or their guardian understands the benefits and the risks of using pain management options. In some cases, the pain management options might shorten the life of a dying patient.
Pain is classified as acute meaning it is short term or chronic when it is long-lasting. Chronic pain can be continuous with periods of intense rise in intensity referred to as flares or intermittent where there are painless periods interspersed with pain periods. Even in cases where the pain is well controlled using long-acting drugs and any other treatment, there might be flares referred to as breakthrough pain. These will however be managed easily using quick acting analgesics.
Most of the patients with chronic pain will also have attention and memory problems. Psychological testing has also indicated that pain is associated with attention, memory, mental flexibility, thinking speed and verbal ability problems. Pain is also linked to an increase in anxiety, depression, anger and fear. Persistent pain will reduce the quality of life of a patient and render them unable to take part in normal daily life activities.
There are cases where pain coming from a certain part of the body feels like it is coming from another part of the body. This is what is known as referred pain. Cancer pain can result from the chemical such as inflammation, or mechanical such as pinching of pain-signaling nerve endings in the body. The pain might also be caused by damaged or diseased nerves and in this case, it is known as neuropathic pain. The pain intensity is described using a scale of 0 to 10 with 0 being no pain at all and 10 being the worst pain the patient has ever experienced.
About 75% of pain caused by cancer is as a result of the illness itself and the other percentage is covered by diagnostic and treatment procedures. Tumors can cause pain especially if they are infiltrating or crushing tissue triggering infections and inflammation or causing the release of chemicals that will make non-painful stimuli extremely painful.
Diagnostic procedures might also cause cancer pain such as venipuncture, lumbar puncture, thoracentesis and paracentesis. There are treatments that are potential causes of cancer pain such as radiotherapy, immunotherapy, chemotherapy, hormone therapy, targeted therapies such as rutuximab and trastuzumab. The infection of the tumors might cause chemical changes and this is known to escalate pain in the surrounding tissues.
Management of Cancer Pain
Cancer pain management is aimed at relieving pain without causing adverse effects with the treatment thus allowing the patient to have a better quality of life and in some case offer a painless death. Though up to 90% cancer pain cases can be controlled a large number of people do not get the medical attention required to effectively deal with the pain.
The pain management needs to be flexible because cancer is known to change over time. There might be a need for a number of different cancer pain management methods as the illness progresses. The medical practitioner managing the pain should explain to the patient the reason why they are experiencing pain and the different treatments available. The most important element of the cancer pain management methods is to relieve the social psychological and spiritual distress. Patients with pain that appears to be uncontrollable should be referred to pain management clinics, pain management specialist or palliative care.
Cancer Pain Medication
The guidelines by WHO recommend prompt oral administration of medication when pain occurs and when it is starting. When an individual is not under severe pain the management involves non-opioid drugs like dipyrone, paracetamol, COX-2 inhibitors among others. When the pain is not relived using the non-opioid drugs, mild opioids may be used. These include tramadol, dihydrocodeine, dextropopoxyphene and codeine. When the mild opioids fail to relive the pain, then they are replaced by stronger opioids like morphine on top of the non-opioid therapy is administered. This is continued to the point of relief with tolerable side effects. If the cause of the pain is severe cancer, all the steps should be skipped and the administration of strong opioids should start combined with non-opioid analgesic.
Anxiety reduction can decrease the pain’s unpleasantness but this will be least effective in moderate to severe cases. Since major tranquilizers, benzodiazepines and anxiolytics are used in sedation, they should be used to only address the depression, anxiety, muscle spasm and disturbed sleep.
It is important that all patients and their guardians understand the benefit and risks of cancer pain management options and it is important that the pain manager follows the right procedures in the administration of the pain management medication.