Intraoperative Radiation Therapy Versus Whole Breast Radiation for Early-Stage Breast Cancer Treatment in Rural Appalachia.

Abstract

Intraoperative radiation therapy (IORT) is an alternate accelerated form of radiation following breast-conserving surgery (BCS). Lack of data regarding long-term outcomes has limited adoption. We report our experience with IORT in patients undergoing BCS versus whole breast radiation therapy (WBRT). Retrospective review of patients undergoing BCS with IORT versus WBRT (2012-2017). Inclusion: low grade, T1-2N0M0, estrogen receptor/progesterone receptor positive, and Her2-negative infiltrating ductal carcinomas. IORT was delivered as a single fraction of radiation (20 Gy) intraoperatively. Outcomes were compared using Fisher's test for discrete variables or Wilcoxon signed-rank test for continuous variables. Kaplan-Meier method was used to estimate disease-free survival (DFS). Fifty-one patients (44%) received IORT, and 66 (56%) received WBRT. There was no difference in age, tumor size, receptor status, or in-breast recurrence (1.9% vs 0%, all P > .05). Length of follow-up was longer in the WBRT group due to time to inception of IORT (mean ± SD: 44 ± 8.1 vs 73 ± 13 months, P < .001). There was no difference in DFS between the 2 groups (HR 2.5; P = .44). IORT patients experienced delay to BCS (mean ± SD: 38 ± 12.7 vs 27 ± 12.2 days, P < .001) likely due to coordination of care. Analysis demonstrated IORT patients would have traveled a mean distance of 20 miles to the closest WBRT center (range 1-70, miles) for a mean travel time of 31 minutes (range 4-90, minutes) per WBRT treatment. IORT produces noninferior oncologic outcomes and decreased skin toxicity compared with WBRT. It can be convenient for patients in rural regions with limited health care access.