Mechanisms that generate and maintain bone cancer pain

Although bone cancer pain can be severe and is relatively common, as it frequently arises from metastases from breast, prostate, and lung tumours, very little is known about the basic mechanisms that generate and maintain this chronic pain. To begin to define the mechanisms that give rise to bone cancer pain, we have developed mouse and rat models using the intramedullary injection and containment of tumour cells into the femur. These tumour cells induced bone remodelling as well as ongoing and movement evoked pain behaviours similar to that found in patients with bone cancer pain. In addition there is a significant reorganization of the spinal cord that received sensory input from the cancerous bone and this reorganization generated a neurochemical signature of bone cancer pain that is both dramatic and significantly different from that observed in mouse and rat models of chronic neuropathic or inflammatory pain. These models have provided insight into the mechanisms that drive cancer pain and have begun to allow the development of mechanism-based therapies. Together these advances should reduce tumour-induced pain and suffering and significantly improve the quality of life of cancer patients.