Collagen vascular diseases and enhanced radiotherapy-induced normal tissue effects--a case report and a review of published studies.

Collagen vascular diseases (CVD) are a group of chronic, autoimmune conditions that can affect multiple organ systems. The mainstay of treatment involves the use of immunosuppressants. CVDs and immunosuppression increase the risk of these patients developing malignancy. The mechanisms through which these patients develop CVDs show similarities to those for radiotherapy late effects, especially fibrosis (via transforming growth factor β). Radiotherapy may in fact cause an active state to develop from a quiescent state of CVD, or exacerbate a pre-existing CVD. CVDs are said to be associated with increased normal tissue toxicity after radiotherapy. Here we present a case report of a patient with a long history of systemic lupus erythematosus and oropharyngeal carcinoma, treated with synchronous chemoradiotherapy. We also review published studies and formulate some guidance on the radiotherapy management of these patients.