What Is Cancer Pain?
Cancer pain explained by San Antonio, Austin, Houston, Dallas Texas top pain doctors
Cancer is associated with high degrees of pain and discomfort. Previous findings have suggested that around half of patients diagnosed with a malignant tumor are currently experiencing severe and impairing degrees of cancer pain. Patients with cancer at the more advanced stages are particularly at risk for severe pain. Estimates have revealed that around two-thirds of patients with advanced forms of cancer suffer from debilitating pain that has begun to impact their sleep, mood, and interpersonal relationships.
Cancer pain may be localized to the area of the malignant tumor or it may be more widespread and permeate to other areas of the body. The severity of cancer pain is impacted by the stage of the disease. Indeed, patients with advanced forms of cancer are more at risk for severe degrees of pain. Moreover, cancer affecting the bone tissue, breast tissue, or the prostate is associated with higher patient ratings of pain.
Damage caused by the growth of a malignant tumor is not the only source of cancer pain. Many of the procedures commonly used to diagnose and treat cancer are associated with risk for pain and discomfort.
Causes Of Cancer Pain
Cancer pain may emerge from a number of different sources, including damage caused by the growing tumor, side effects related to the diagnostic procedures and treatment interventions, as well as infection of the tumor.
A portion of reported cancer pain is attributable to the growth of the tumor itself. This leads to an increased pressure placed upon the tissue surrounding the tumor, such as lung tissue, brain tissue, blood vessels, nerve fibers, the spinal cord, connective tissue, and the tissue of other organs. Pressure and tissue compression can lead to irritation and inflammation of these structures, which may be attributed to increased pain.
Cancerous tumors can also invade the bone tissue of the body, which frequently leads to symptoms of tenderness and soreness. Patients suffering from bone damage attributable to the growth of a tumor tend to report experiencing more severe degrees of pain.
While there are no pain sensors located within the brain, brain tumors can be the source of significant pain and discomfort. Brain tumors can cause compression of the protective membranes that encapsulate the brain, known as the meninges, as well as the blood vessels located throughout the brain, resulting in irritation, inflammation, and pain. Cancerous tumors can also cause a build-up of excess fluid within the brain. This extra fluid undoubtedly places pressure on these structures as well, resulting in significant pain.
The process of diagnosing and treating cancer can be especially painful for the patient, both mentally and physically. Many of the procedures commonly used with cancer patients carry risks for painful side effects.
The lumbar puncture (i.e., spinal tap), for example, is a procedure commonly used to collect samples of cerebrospinal fluid (CSF) or to inject medications directly into the CSF, such as during chemotherapy or when administering spinal anesthesia. During this procedure, a hollow needle, known as a cannula, is inserted in between two vertebrae within the lumbar region of the spinal cord. Patients may experience headaches or back pain as a result of this procedure.
Thoracentesis, a procedure used in both the diagnosis and treatment of cancer, also involves inserting a cannula into the thorax region. This technique can be used to collect samples of pleural fluid or to remove excess fluid, caused by the cancerous tumor, from the pleural space. As with the lumbar puncture procedure, there is an increased risk of pain and discomfort following a thoracentesis.
Both paracentesis and venipuncture are also associated with some risk for pain and discomfort following the procedure, though it is not as common.
Treatments involving both chemical or radiation therapy can be particularly painful for cancer patients. The goal of these types of treatment is to damage or destroy the cancer cells, and there are significant side effects associated with both. Patients undergoing chemotherapy frequently report side effects of joint or muscle pain, mucositis, and peripheral neuropathy.
It is also common for chemotherapy patients to complain of abdominal pain that may be attributable to diarrhea or constipation, which are side effects from this treatment. Patients receiving radiotherapy commonly experience side effects of skin reactions, fibrosis, enteritis, myelopathy, neuropathy, bone necrosis, and plexopathy. Both chemotherapy and radiotherapy may result in significant nerve and tissue damage, which may place the patient at increased risk for chronic pain.
Surgically removing the cancerous tumor is also likely to lead to pain complaints. It is not uncommon for cancer patients to suffer from significant post-operative pain following these surgeries.
Cancer pain that occurs rapidly and escalates in severity very quickly may be related to an underlying infection of the tumor. A previously conducted survey of cancer patients who had been referred for the treatment of their cancer pain found that around 4% of the cases of pain were attributable to an infection within the tumor.
Treatment For Cancer Pain
Treatments targeting the transmission of pain signals within the spinal cord are among the most effective methods of managing cancer pain. Indeed, the spinal cord acts by transmitting pain signals from the pain site to the brain.
Opioid medications, such as fentanyl, morphine, or codeine, are one available treatment option for cancer patients that work in this way. Opioid medications provide relief from cancer pain by activating opioid receptors within the spine, which then inhibit the flow of pain signals through the spinal cord. There is some risk associated with opioid medication use. Opioid medications are highly addicting, thus patients must be monitored carefully and regularly for possible abuse or misuse. Further, cancer patients are also at risk for developing a tolerance to the medication. As such, the drug’s effect weakens over time leading the patient to need increasingly higher doses to achieve relief.
Spinal cord injections are another option for the treatment of cancer pain. Spinal cord injections are minimally invasive and can be performed on an outpatient basis. For this procedure, an anesthetic is injected into the spinal cord region. The location of the injection largely depends on the location of the tumor. The injection is generally placed in the region of the spinal cord that controls that particular area of the body. Patients receiving spinal cord injections have reported improvements in the severity of their cancer pain. Indeed, some patients achieved total relief from pain following this procedure.
Nonetheless, there are some risks associated with spinal cord injections. These risks include numbness, nerve damage, and respiratory distress, and can generally be attributed to the improper placement of the injection needle. In relatively few cases, spinal cord injections have resulted in paralysis.
Pain suffered by cancer patients is not fully attributable to the cancerous tumor itself. Indeed, procedures used to diagnose and treat the tumor are accompanied by risks for pain and discomfort. In general, tissue and nerve damage is the most common cause of cancer pain. This can be caused by the growth of the tumor placing pressure on the surrounding tissue or by the invasive procedures used to assess and eradicate the cancer cells. Instances of cancer pain that occur very suddenly and increase in severity rapidly may be linked to an underlying infection within the tumor.
When treating cancer pain, physicians and health care providers target the transmission of pain signals up and down the spinal cord. Opioid medications, for instance, inhibit the transmission of pain signals by activating the opioid receptors along the spinal cord. Spinal cord injections work by injecting an anesthetic into a region of the spinal cord to block this flow of information. It is recommended that individuals speak with their physician or health care provider about appropriate options for managing cancer pain.
- Rodriguez CG, Lyras L, Gayoso LO, et al. Cancer-related neuropathic pain in out-patient oncology clinics: a European survey. BMC palliative care. 2013;12(1):41.
- Peng PW, Castano ED. Survey of chronic pain practice by anesthesiologists in Canada. Canadian journal of anaesthesia = Journal canadien d’anesthesie. 2005;52(4):383-389.
- Malhotra VT, Root J, Kesselbrenner J, et al. Intrathecal pain pump infusions for intractable cancer pain: an algorithm for dosing without a neuraxial trial. Anesthesia and analgesia. 2013;116(6):1364-1370.
- Ives TJ, Chelminski PR, Hammett-Stabler CA, et al. Predictors of opioid misuse in patients with chronic pain: a prospective cohort study. BMC Health Services Research. 2006;4;6:46.
- Gulati A, Khelemsky Y, Loh J, Puttanniah V, Malhotra V, Cubert K. The use of lumbar sympathetic blockade at L4 for management of malignancy-related bladder spasms. Pain physician. 2011;14(3):305-310.
- Deer TR, Skaribas IM, Haider N, et al. Effectiveness of Cervical Spinal Cord Stimulation for the Management of Chronic Pain. Neuromodulation : journal of the International Neuromodulation Society. Sep 24 2013.
- Neurolytic celiac plexus block for pain control in unresectable pancreatic cancer. Yan BM, Myers RP. Am J Gastroenterol. 2007;102(2):430-8.