Does the number of surgical excisions before delivering intraoperative radiotherapy (IORT) affect skin toxicity

72 Background: The TARGIT-A trial allowed administration of IORT both pre- and post-pathology. The advantage of post-pathology is the ability to determine eligibility based on margins, pathologic tumor size and nodal status, prior to delivering radiation. However, it is unclear whether having more than one operation before IORT is associated with worse skin toxicity. In this study, we aimed to examine the relationship of the number of operations and skin toxicities in women receiving IORT. Methods: We conducted a retrospective analysis of 57 consecutive patients who underwent IORT from 2009-2013. All patients received 20 Gy in 1 fraction prescribed to the applicator surface using the Carl Zeiss Intrabeam System. Skin toxicities were determined using CTCAE 4.0 and RTOG criteria. In addition, infection, skin erythema, desquamation, symptomatic seroma, and necrosis were scored individually and used as outcome measures. Pearson’s Chi-squared test was used to assess the association of the number of operations ...