Intraoperative Radiation Therapy as a Safe Alternative to Whole Breast Radiation for Treatment of Minimally Invasive Breast Cancers: A Retrospective Cohort Study.

Background: Intraoperative radiation therapy (IORT) in select populations is a viable alternative to whole breast radiation therapy (WBRT) in the treatment of biopsy-proven localized invasive and non-invasive breast cancer. We aim to assess recurrence and complication rates following IORT in lumpectomy patients at a community hospital in Baltimore City.

Methods: An IRB-approved retrospective cohort study was conducted on consecutive cases of lumpectomy with IORT from 2013 through 2020 by a single surgeon. Patient demographics, tumor and operative characteristics, and complications were retrieved from electronic medical records. Primary outcomes were postoperative complications and local recurrence rates.

Results: The final cohort included 117 patients with mean follow-up time of 2.60 + 1.78 years. Mean age was 69.84 + 8.77 years. Thirty-three (28.21%) of patients developed a seroma. Odds of seroma formation were mildly significant for skin spacing [OR: 1.18, 95% CI: (1.02-1.37)] and balloon fill volume [1.04 (1.00-1.08)], but not for age, BMI, diabetes, former or current smoking status, history of WBRT, tumor size, or balloon size. Three (2.6%) patients had local recurrence. Odds of local recurrence were mildly significant for increased tumor size [1.14 (1.04-1.24)] and not significant for any other covariates.

Conclusions: IORT exposure did not confer higher rates of complications and the local recurrence rate mirrored that of the general population undergoing lumpectomy and WBRT. This study demonstrates the need for equitable treatment options based on individual needs: IORT is a safe alternative to WBRT in certain subpopulations, especially those with physical, social, or personal limitations preventing participation in a 3- to 7-week time commitment of WBRT.