Pain is prevalent and often under-treated in cancer patients. It may arise from a tumor compressing or infiltrating nearby body parts; from treatments and diagnostic procedures; or from skin, nerve and other changes caused by a hormone imbalance or immune response. It is important to distinguish between persistent and breakthrough pain. Most chronic (long-term) pain is caused by the illness, and most acute (short-term) pain is caused by treatment or diagnostic procedures.

Intrathecal pain pumps can be used to help treat cancer pain.