Treatment of cancer pain can be very complicated, depending on whether the cancer itself or a related condition is causing the pain.
To understand what can be involved with cancer pain and why it occurs, it’s important to understand the basics about what cancer is and how it behaves.
Cancer is the uncontrollable growth of abnormal cells in the body. These cancer cells destroy normal, healthy cells, causing a wide variety of serious conditions. Although cancer treatments continue to improve, cancer is still the second leading cause of death in the United States.
One out of every three people diagnosed with cancer will suffer from cancer pain, and those whose cancer is in the advanced stages have higher chances of suffering from cancer pain.
The pain may be dull, achy and constant, or it may be severe and periodic. The pain may result from the cancer itself as it destroys healthy tissue, or the growing tumor may place pressure on organs, nerves, bones or other tissues. Certain functions of cells and the rest of the body may also be impaired due to the destruction of healthy tissue.
Some cancers release chemicals as the cancer grows and spreads (metastasizes), and these chemicals can contribute to the patient’s pain. Cancer treatments and medications may also have painful effects.
Cancer pain symptoms, as well as related symptoms, can include:
Indigestion or upset stomach
Sores (such as on the skin)
Changes in bowel or bladder habits
As mentioned above, cancer treatments are also potentially painful for the patient. Chemotherapy is typically very unpleasant for cancer patients, and can cause sores, diarrhea, nerve damage, fatigue and other painful side effects. Radiation treatments have been known to cause burning sensations and leave scars that are painful. And a patient’s body may require a long time to heal following surgery, for example, a procedure to remove the cancerous growth and other tissue the cancer destroyed.
Other methods of treating cancer pain include over-the-counter medications, prescription medications, or opioids (codeine, morphine, oxycodone, methadone) to make the patient more comfortable.
Usually the treatment of cancer pain involves removing the cancer itself, using the therapies mentioned above and others. Although many of the treatments themselves will cause pain, the long-term goal is to save the patient’s life and restore as much of his or her quality of life as possible.
The best cancer treatment programs will take into consideration not just the patient’s physical condition, but also his or her mind-body connection — in other words, the patient’s sense of overall well-being. For this reason doctors will often design treatment plans that incorporate a number of different therapies, including nerve blocks, meditation, rest, acupuncture, acupressure, physical therapy, massage and others.
It is widely known that individuals diagnosed with almost any type of cancer are at risk for enduring severe degrees of pain. In fact, some have estimated that, at any given time, approximately half of all patients diagnosed with a malignant tumor are enduring significant levels of pain. Moreover, of the patients who are reported to have more advanced forms of the disease, it has been estimated that around two-thirds are exhibiting such high degrees of pain that it has begun to have deleterious effects on their ability to function, their sleep, social relations, and their mood.
The pain associated with cancer may be localized to the area afflicted with the malignant tumor or it can be felt in other areas of the body. The degree of pain experienced has also been found to correlate with the stage of the disease. Patients diagnosed with breast, bone, or prostate cancers have been found to report the most severe levels of pain.
Cancer pain is not solely attributable to the damage caused by the tumor itself. In fact, the procedures and treatment for the condition are also accompanied by pain and discomfort for the patient.
Causes Of Cancer Pain
As noted, there are many potential sources of pain for patients suffering from a malignant tumor. These sources include:
The tumor itself
Procedures utilized during diagnosis of the disease
Treatment of the disease
Infections occurring on the tumor or in the surrounding tissue
In terms of the tumor, pain can be triggered in several ways. One way is by the tumor compressing or permeating the surrounding tissue. For instance, growing tumors can apply increasing amounts of pressure on nearby, unaffected tissue, including blood vessels, the heart, lungs, nerve fibers, spinal cord, brain, various connective tissue, and other organs. This compression causes nearby, benign tissue to become irritated, inflamed, and sore.
Malignant tumors also have the potential to invade bone structures within the body. When this occurs, patients generally report sensations of tenderness and soreness. Cancer pain that occurs as the result of bone damage from the tumor is generally regarded as the most severe form of cancer pain.
While the brain itself is free from pain sensors, tumors occurring within the brain can be a source of pain and discomfort by applying pressure to the meninges (i.e., the protective membrane encapsulating the brain) or blood vessels. Brain tumors may also lead to a build-up of excess fluid within the brain, which can also cause pressure-related cancer pain.
Procedures used in diagnosing and treating cancerous tumors can be associated with reports of pain or discomfort. For instance, the lumbar puncture, which is also known as the spinal tap, involves inserting a spinal needle between two vertebrae within the lumbar region. This procedure is employed in order to collect a sample of cerebrospinal fluid for evaluation or to inject treatment medications directly into the cerebrospinal fluid (typically done during chemotherapy or for administering spinal anesthesia). It is associated with reports of headache and back pain.
Another procedure often used in the diagnosis and treatment of cancer is the thoracentesis. During this procedure, a hollow needle, known as the cannula, is inserted into the thorax region (i.e., the chest) to remove excess build-up of fluid from within the pleural space. Similar to the lumbar puncture, the thoracentesis has been linked with an increased risk for pain and discomfort.
Though not as common, paracentesis and venipuncture have also been found to cause significant pain and discomfort to patients with cancer.
Both chemo- and radiotherapy are associated with significant pain and discomfort. Chemotherapy is known to cause joint pain, muscle pain, mucositis, and peripheral neuropathy. Further, patients undergoing chemotherapy often have complaints of abdominal pain owing to diarrhea and constipation caused by treatment. Radiotherapy has been linked with an increased risk of developing skin reactions, myelopathy, fibrosis, enteritis, bone necrosis, neuropathy, and plexopathy. Nerve and tissue damage caused by cancer treatments using chemicals or radiation can lead to problems associated with chronic pain.
Surgical removal of the tumor is linked with risk for pain, as patients are likely to suffer from significant post-operative pain.
Finally, infections that can develop within a malignant tumor have been found to cause a rapid onset of severe pain. Cancer pain related to tumor infection can be frequently overlooked. In fact, a survey of cancer patients referred for pain management found that 4% of patients were experiencing cancer pain owing to an infection that had developed within the tumor.
Treatment For Cancer Pain
The most effective treatments for cancer pain generally target the spinal cord. The spinal cord is responsible for relaying pain signals from the source of the pain to the brain. Thus, by inhibiting this transmission of pain information between the various parts of the body, the individual will be afforded relief from the pain sensations.
One method of blocking the transmission of pain information is through the pharmacological use of opioid medications (e.g., codeine, fentanyl, or morphine). These medications are effective in reducing cancer pain by activating the opioid receptors within the spine. These receptors act to inhibit the transmission of pain signals.
While opioid medications are effective for treating the pain associated with cancer, patients are at risk for becoming psychologically or physically dependent on the drug. Moreover, patients being treated with opioids can become tolerant of the drug’s effect. Thus, the medication becomes increasingly less effective at managing the patient’s symptoms of pain over time.
Alternative treatments include spinal cord injections. These treatments are minimally invasive and work by injecting an anesthetic to inhibit the transmission of pain signals within the spinal cord. The location of the injection is dependent upon the spinal nerves responsible for the area of the body affected by the tumor. Following these treatments, many patients report significant improvements in the severity of their pain. Some patients have experienced total relief from pain and discomfort as a result of these injections.
Though spinal cord injections are minimally invasive, there are some risks associated with the procedure. These risks are generally attributed to improper placement of the injection needle and may include nerve damage, numbness, and respiratory depression. In severe cases, paralysis may result.
Cancer pain may be caused by a number of different sources. Tissue or nerve damage is one particular source of cancer pain. This can occur both by the growth of the malignant tumor, as well as through the procedures used for diagnosing and treating the cancer. Infection of the tumor has also been linked to sudden-onset cancer pain.
Treatments available to assist cancer patients in managing cancer pain target the transmission of pain signals within the spinal cord leading to the brain. These treatments include opioid medications and spinal cord injections. Individuals are encouraged to speak with the physician or health care provider about the treatment options available for cancer pain.
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