LATE RADIATION-INJURY TO MUSCLE AND PERIPHERAL-NERVES

Late radiation injury to muscles and peripheral nerves is infrequently observed. However, the success of radiation oncology has led to longe r patient survival, providing a greater opportunity for late effects t o develop, increase in severity and, possibly, impact the quality of l ife of the patient. In addition, when radiation therapy is combined wi th surgery and/or chemotherapy, the risk of late complications is like ly to increase. It is clear that the incidence of complications involv ing muscles and nerves increases with time following radiation. The in fluence of volume has yet to be determined; however, an increased volu me is likely to increase the risk of injury to muscles and nerves. Exp erimental and clinical studies have indicated that the alpha/beta rati o for muscle is approximately 4 Gy and, possibly, 2 Gy for peripheral nerve, indicating the great influence of fractionation on response of these tissues. This is of concern for intraoperative radiation therapy , and for high dose rate brachytherapy. This review of clinical and ex perimental data discusses the response of muscle and nerves fate after radiation therapy. A grading system has been proposed and endpoints s uggested.