Neuromuscular complications of radiation therapy.

Neuromuscular late effects of radiation therapy (RT) result from radiation fibrosis (RF) of the treated tissues. The clinical manifestations of this dysfunction have been termed radiation fibrosis syndrome (RFS). Any segment of the central and/or peripheral nervous system can be involved, including the brain, spinal cord, nerve roots, plexus, peripheral nerves, and muscles. Often, multiple levels are damaged, resulting in a constellation of findings named for the affected structures (i.e., radiculo-plexo-neuro-myopathy). Accurately diagnosing RFS requires the clinician to understand the basics of how radiation is and has been delivered. Key parameters of RT delivery include total dose, dose per fraction, and the radiation field treated. This article describes the basic principles of RT delivery, the pathophysiology of radiation injury, and how to identify and evaluate neuromuscular late effects of radiation in cancer survivors. Muscle Nerve 56: 1031-1040, 2017.