What are the different causes of pain in a cancer patient?
There are multiple causes of cancer pain. Approximately 65% of cases are caused by the cancer itself, either by direct invasion, involvement of nerves or the neuroaxis, obstruction of a viscus, or metastasis to a distant tissue. Anticancer treatments are responsible for 25% of cancer pain. These include surgery, diagnostic procedures, chemotherapy side-effects, and radiation complications. Syndromes unrelated to the cancer cause the remaining 10% of pain in the cancer patient. It is important to remember that patients with cancer may also have common noncancer-related pain syndromes such as lower back pain and headaches.