Mechanisms of cancer‒induced pain

Abstract

Many advanced and terminal cancer patients must cope with chronic severe pain. In orofacial cancer patients, difficulties in eating and swallowing can readily lead more severe symptoms than found in cancers of other regions. Because cancer pain is sometimes intractable, there is an urgent need to improve the quality of life of patients with incurable cancer and to seek means to prevent the development of cancer pain. To understand mechanism of cancer‒induced pain, it is important to develop model animals. Although many cancer‒pain models have been already reported and studied, they have been developed by targeting the sciatic nerve area, not the trigeminal nerve area, which is concerned with nociceptive signals in the orofacial region. Therefore, to study effect of cancer on the trigeminal nerve, we have developed a rat facial cancer model by inoculating Walker carcinosarcoma 256B cells, and have revealed some characteristics in the mechanisms of facial cancer‒induced pain. In this review, we introduce our developed model for facial cancer pain and recent accumulated evidence for understanding the mechanisms of cancer‒induced pain.