Comparative safety and short-term outcomes of intraoperative radiotherapy versus neoadjuvant chemoradiotherapy in locally advanced rectal cancer: a retrospective study

Purpose: Neoadjuvant chemoradiotherapy (nCRT) constitutes an integral component of the standard therapeutic strategy for locally advanced rectal cancer (LARC) but carries cumulative toxicity, cost, and occasional non-response. Intraoperative radiotherapy (IORT) delivers a single high dosage directly to the tumor bed and may overcome these limitations. We compared short-term efficacy and safety of low-kilovoltage(kV) x-ray IORT with long-course nCRT. Methods: LARC patients treated at Maoming People's Hospital (2022-2024) were retrospectively reviewed. The nCRT cohort received 45-50 Gy radiotherapy plus capecitabine before surgery; the IORT cohort underwent INTRABEAM low-kV x-ray IORT (12.5-20 Gy) during surgery. Disease-free survival (DFS), overall survival (OS), postoperative complications, and recurrence were analyzed. Survival was estimated by Kaplan-Meier curves. Results: = 0.864) did not differ between IORT and nCRT. Early postoperative bowel obstruction and urinary retention were more frequent after IORT, although neither difference was significant; long-term complications and recurrence patterns remained comparable between the groups. Conclusion: Single-fraction low-kV IORT provides short-term survival equivalent to standard nCRT with acceptable perioperative safety. It is a viable option for LARC patients unable or unwilling to undergo prolonged nCRT, although vigilance for early gastrointestinal and urinary complications is warranted.