Long‑term follow‑up outcomes of intraoperative radiotherapy for breast‑conserving treatment in early breast cancer: A retrospective cohort study

Intraoperative radiotherapy (IORT) has been used as a novel therapeutic alternative for breast-conserving surgery (BCS) in patients with breast cancer. However, the long-term outcomes and safety of IORT in patients with breast cancer remain incompletely understood. Therefore, the present study aimed to explore the long-term outcomes of IORT following BCS, focusing on the oncological outcomes and cosmetic consequences compared with postoperative RT (PORT) in patients with breast cancer. Patients with early-stage breast cancer who underwent BCS followed by IORT or PORT between January 2016 and October 2020 at the Research Institute of General Surgery, Jinling Hospital, Nanjing Medical University (Nanjing, China), were retrospectively reviewed. After screening, a total of 59 patients were included in the present study and divided into two groups according RT records as follows: The IORT group (n=21) and the PORT group (n=38). The clinical data of all patients, including surgical and RT complications, cosmetic grading and scoring, and other events, were collected and retrospectively analyzed. No significant difference was observed in terms of the mean follow-up time in the IORT (5.89±1.57 years) and PORT (6.09±1.60 years) groups (P>0.05). Compared with PORT, IORT showed non-inferior therapeutic efficacy, with no significant differences in postoperative complications (surgical site infection and chronic pain; P>0.05). Notably, the IORT group achieved superior cosmetic outcomes, with 95.2% (20/21) of patients achieving a rating of excellent/good vs. 44.7% (17/38 patients) in the PORT group (P<0.001), alongside higher median cosmetic scores at all postoperative intervals (P<0.01). IORT also reduced healthcare utilization, shortening hospitalization by 23.8 days (12.1±5.1 vs. 35.9±3.5 days; P<0.001) and lowering costs significantly (33,117.98±6,281.17 vs. 77,789.55±7,000.90 CNY; P<0.001). These findings suggest that IORT offers comparable safety, improved cosmesis and greater cost-effectiveness than PORT, supporting its integration into clinical practice for eligible patients.