Intraoperative radiation therapy for breast cancer—Immediate and 30-month oncological outcomes

There is growing evidence that intraoperative radiation therapy (IORT) may be a viable option in selected patients with early breast cancer. This study reports our 4-year experience with IORT. The perioperative outcome and imaging data of all patients who underwent IORT for early breast cancer at a tertiary medical center in 2014-2018 were retrospectively retrieved. The cohort included 158 patients aged 52-84 years (mean 68) with stage I (n = 137) or II (n = 21) breast cancer. Mean applicator size was 4.13 cm; IORT added a mean of 29 minutes to the operative time. Minor wound infections (n = 18, 11.4%) requiring antibiotics and drainage were the only postoperative complication. In 25 patients (15%), postoperative mammography demonstrated a seroma (n = 22) or fat necrosis (n = 3). The risk of wound infection or a new postoperative imaging finding was unrelated to patient age, operative time, tumor size, or comorbid diabetes or obesity. After a mean of 30 months' follow-up, none of the patients who met the institutional criteria for IORT had local recurrence, regardless of age, histology, tumor grade, KI67 proliferation index, pathologic stage, Recurrence Score, or additional whole-breast irradiation or adjuvant treatment. Patients for whom a Recurrence Score was determined (n = 55, 35%) had a significantly higher tumor grade, pathologic stage, and whole-breast irradiation/adjuvant chemotherapy rate than the remaining patients. IORT may be a safe alternative to traditional external beam radiation in well-selected patients with early breast cancer, with few minor complications and good 30-month outcome.