Elevated Radiation Therapy Toxicity in the Setting of Germline PTEN Mutation

Cells that lack PTEN function are radiation sensitive in cell culture-based experimental systems; therefore, patients with Cowden Syndrome (CS) may carry an increased risk for normal tissue injury after radiotherapy. Here we present the first such case of a patient with genetically-confirmed CS who, indeed, experienced greater than expected toxicity following two separate courses of radiotherapy. While a causal relationship between CS and radiation sensitivity remains unclear, this observation suggests the need for further study in larger cohorts of CS patients.