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

## TL;DR

This study compares the safety and short-term outcomes of intraoperative radiotherapy and neoadjuvant chemoradiotherapy for rectal cancer, finding similar survival rates but different complication profiles.

## Contribution

Demonstrates that single-fraction low-kV IORT is a viable alternative to standard nCRT for locally advanced rectal cancer.

## Key findings

- No significant difference in disease-free or overall survival between IORT and nCRT groups.
- Early postoperative complications were more frequent with IORT but not statistically significant.
- Long-term complications and recurrence patterns were comparable between the two treatment groups.

## Abstract

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.

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.

A total of 67 patients were included (46 in nCRT, 21 in IORT). Kaplan–Meier analysis showed no significant difference in DFS or OS between the IORT and nCRT groups (DFS P = 0.669; OS P = 0.864). 3-year DFS (53.7% vs. 52.8%, P = 0.669) and OS (89.0% vs. 78.4%, P = 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.

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.