Causes of cancer pain

Lore & Background

Cancer pain can be caused by pressure on or chemical stimulation of nociceptors (nociceptive pain) or by damage to nerve fibers (neuropathic pain). Infection of a tumor or its surrounding tissue can cause rapidly escalating pain, though it is sometimes overlooked; one study found infection as the cause in four percent of nearly 300 cancer patients referred for pain relief. Tumors can crush or infiltrate tissue, or release chemicals that make nociceptors responsive to normally non-painful stimuli.

Reader's Guide

Vascular events such as deep vein thrombosis (caused by cancer in 15 to 25 percent of cases) and superior vena cava syndrome (often from lung cancer) produce pain and swelling. Nervous system causes include brain tumors pressing on blood vessels or meninges, meningeal carcinomatosis (first symptoms often severe back pain and headache), spinal cord compression (about three percent of patients), nerve infiltration, dorsal root ganglion inflammation, and brachial plexopathy. Bone invasion is the most common source of cancer pain, affecting 70 percent of breast and prostate cancer patients, with fractures causing sudden severe pain. Visceral pain from organs like the liver, kidneys, and pancreas is diffuse and often referred; pancreatic body or tail cancer causes pain in 10 percent of patients, while 90 percent of those with other pancreatic locations experience pain.

Did You Know?

• Between 15 and 25 percent of deep vein thrombosis is caused by cancer.
• About 70 percent of breast and prostate cancer patients develop bone metastases.
• Ten percent of patients with cancer spreading to different parts of the body develop meningeal carcinomatosis.