Sources of cancer pain
Pain in people with cancer can be complicated because several things may cause it. How the pain varies from person to person depends on the type of cancer, its treatment and other conditions that co-exist with the cancer.
Cancer pain can be caused by several factors:
- Cancer can cause neuropathic pain. Neuropathic pain is caused by damage to the nerve. Nerve damage may be caused by the cancer tumor itself, or by the tumor or tumors pressing on a nerve or blocking the blood supply to a nerve. Anticancer drug therapy and surgery may also cause neuropathic pain.
- Tissues damaged by cancer can release chemicals that trigger an inflammatory process, eventually leading to inflammatory pain. These chemicals can increase activity in pain receptors and make nerve fibers more sensitive to pain.
- Cancer can also be accompanied by visceral pain, meaning pain in internal organs. This kind of cancer pain may be caused by tumors pressing on, stretching or blocking the blood supply to internal organs, or by inflammation from damage to the internal organ tissues.
- If cancer spreads to bones around the body, it can cause musculoskeletal (or somatic) pain. Bones have many nerve fibers, so bone damage from cancer can trigger pain.
- Pain can also result from cancer therapy. There are some chemotherapy drugs that can cause nerve pain. Chemotherapy can also cause painful mouth sores (oral mucositis) that can affect eating, drinking or talking. Pain can also come from the surgery to remove tumors. Radiation can lead to skin burns, mucositis and scarring, all of which can be painful.
- Phantom pain can occur after an arm, leg or even a breast is removed. The person may still feel pain or other unusual or unpleasant feelings that seem to be coming from the absent body part.
The importance of treating cancer pain
Controlling cancer pain is an important part of cancer management. Most cases of cancer pain can be treated to help minimize discomfort and stress.
Although cancer pain may not always be relieved completely, there are ways to help control the level of pain in most patients. This is important because pain control helps improve quality of life. A person in pain may not feel able to carry out his or her daily activities and may experience changes in mood that could affect relationships. When pain is not controlled, one can easily feel frustrated and alone, particularly when family and friends do not understand what’s going on.
People with cancer have a right to pain control and should be honest about their pain with their medical team. Pain is not a normal part of cancer. Telling the healthcare team early is important because pain is easier to treat when it is just beginning. Also, pain could point to a developing, previously unidentified, problem, or be a warning sign of the side effects of cancer treatment. Each person needs an individualized plan to control cancer pain.
Treating cancer pain
Together, the patient and the healthcare team will work out the best combination of pain treatments with the fewest side effects. A patient’s input is important so the medical team can adjust pain treatment according to how the patient is responding.
Most cancer pain patients will get some pain relief with a combination of medications. Some drugs are general pain relievers (analgesics), while others target specific types of pain. Analgesics such as paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs), like ibuprofen or aspirin, are good for mild pain but generally will not provide adequate levels of control for cancer pain. They need to be combined with other medicines, such as opioid analgesics, or medicines such as antidepressants and anti-epileptics, which can help control pain messages in the nerves. Medicines are usually given orally (by mouth), but can also come in the form of intravenous (IV) drugs (given by injection), skin patches or rectal suppositories. Cancer pain patients need to tell their healthcare team about all the medicines they are taking because some might interact with cancer drugs and cause side effects.
In patients with cancer, doctors may also recommend non-medical treatments for pain. For example: radiation or surgery to shrink or remove a tumor. Nerve blocks, where medicine is injected around a nerve or into the spine to block pain signals, or neurosurgery may also be considered. Other methods may also be recommended to complement medications – these include the use of relaxation and breathing techniques, biofeedback, massage, and hypnosis.