What is Cancer Pain?
Cancer Pain Explained by Las Vegas, Summerlin, and Henderson Nevada’s Top Pain Doctors
Pain can be caused by various types of cancer. This can occur in the region in which the cancer is located, or even in other parts of the body. Breast, prostate, and bone cancers are particularly associated with pain. This can be a chronic condition, caused by tumors pressing against nerves, or infiltrating other tissues.
Pain is also a side-effect of cancer treatments. Chemotherapy and radiotherapy are associated with experiencing pain, and surgeries to remove tumors are obviously a source of pain. The pain resulting from cancer or cancer treatment can be short-term (acute) or chronic. Acute pain often results from cancer treatment, and resolves over time. However, radiation or chemical therapy can also cause damage to nervous tissue, which can cause chronic pain. Chronic pain is also associated with nerve or tissue damage caused by tumors. For these reasons, pain relief is often a component of cancer therapies.
Causes of Cancer Pain
Cancer-related pain is caused directly by tumors, or indirectly as an adverse effect of treatments such as chemotherapy. Tumors can cause pain in a variety of ways; by damaging and infiltrating tissues, physically compressing nerves, and releasing chemicals that irritate or cause inflammation to nervous tissue. Though rare, this tissue can itself become cancerous (e.g. gliomas) which can also be a source of chronic pain. Brain tumors can cause pain by compressing blood vessels and either spreading to, or pressing on the lining of the brain. Tumors can also spread into unrelated tissue, which is also associated with the occurrence of pain. This is particularly true when cancer spreads into bone.
Treatments to reduce or remove cancerous tissue can also cause pain. This is mainly due to tissue or nerve damage caused by surgeries performed to remove tumors. Radio – or chemotherapy can also cause damage to nerves, and produce inflammation as a side-effect, causing a pain response.
Treatment for Cancer Pain
Pain signals travel to the brain via the spinal cord; therefore, the most effective methods of pain relief specifically target this. A pharmacological (drug-based) method of achieving this is through the use of opioid medications. Opioids (e.g. codeine, morphine, and fentanyl) activate opioid receptors in the spine that act to inhibit pain signals. These drugs are often administered to cancer patients orally or intravenously to reduce pain. Opiods are often used in the treatment of acute cancer pain. The risks of using opioids include the potential for addiction. In other words, patients may become psychologically or physically dependent on them. Patients may become tolerant (the same dose of opioids becomes less effective at blocking pain over time) to these medications, making them less of an option in relieving chronic pain.
An alternative to opioids are spinal nerve (or clusters of these, e.g. celiac plexus) injections, which are injections of pain-blocking compounds (anesthetics such as lidocaine, bupivacaine, or mepivacaine) into the space near the affected nerves. The anesthetics used can block the pain signals from going to the brain. The injections can be given at the site of the spinal nerves that are controlling the area of the body affected by tumors or their treatment; for example, if the pain is in the pelvic region, the relevant lumbar or sacral nerves can be injected. A variation on this treatment is a catheter (or intrathecal pump) inserted into the epidural space, which will deliver the anesthetics over time.
The risks of these procedures include nerve damage and improper placement of the injection, which can cause numbness, discomfort, respiratory depression, and paralysis in severe cases. Temporary neurological complications such as nausea and chest numbness can also occur. Another option to relieve chronic pain may be the implantation of a spinal cord stimulator (SCS), which causes interference in pain signaling. SCS carries a low incidence of nerve damage and scarring. Other risks include bleeding and infection at the insertion site.
Cancer-related pain occurs as a result of tissue damage, or nerve damage, caused by tumors as they grow and invade other regions of the body. Treatments to shrink or remove tumors can also cause pain.
Cancer patients are often treated with opioids to relieve this pain. However, these are sometimes associated with addiction and tolerance, so alternatives to these are desirable. These include epidural anesthetic injections, in which pain-blocking drugs are delivered directly to the spinal nerves responsible for sending pain signals to the brain. These carry a low level of risk, including neurological complications. Spinal cord stimulation selectively disrupts the nerves sending painful stimuli. Risks include infection and nerve damage. These methods effectively treat pain associated with cancer or cancer treatment.
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