A rat pain model of facial cancer.

Cancer pain is a very severe problem for patients with advanced or terminal cancer. However, the induction mechanism remains unknown. Orofacial cancer patients often report difficulties in eating and swallowing, different from patients with cancer in other regions. Although several cancer pain animal models have been reported, these models have focused on the sciatic nerve areas. To understand the mechanisms of pain associated with orofacial cancer, we recently created a rat facial cancer model by inoculation of cancer cells into the vibrissal pad. This model provides mechanical allodynia, thermal hyperalgesia, and feeding disorder characteristics, similar to orofacial cancer patients. Hence, this model is useful for the evaluation of cancer pain of the trigeminal nerve area. In this chapter, we describe in detail the generation of a facial cancer pain model of rats by inoculation of Walker carcinosarcoma 256B cells.