Optimal timing of surgery after neoadjuvant chemoradiotherapy in rectal cancer: A retrospective analysis

Background: Determining the optimal interval between neoadjuvant chemoradiotherapy (NCRT) and surgery in patients with locally advanced rectal cancer (LARC) remains crucial for improving treatment outcomes. Extending the interval may increase rates of pathological complete response (pCR), potentially enhancing survival and reducing recurrence. Methods: This retrospective cohort study included 226 patients with LARC who underwent NCRT followed by surgery. ROC analysis was used to establish the optimal interval between NCRT and surgery for achieving pCR, and multivariate logistic regression assessed independent predictors of pCR. Spline regression further analyzed the relationship between surgery timing and the probability of pCR. Results: ROC analysis identified 10.5 weeks as the optimal interval, showing increased pCR rates within this period. Multivariate analysis confirmed that surgery interval (OR = 2.603, P = 0.045) significantly predicted pCR. Both ROC and spline regression indicated that a 9-11-week interval maximizes pCR probability. Notably, the comparison of postoperative complications between groups with surgery intervals <= 10 weeks and >10 weeks showed no statistically significant differences (P = 0.518). Conclusion: An interval of 9-11 weeks between NCRT and surgery optimizes pCR rates without increasing postoperative risks. This timeframe may serve as a favorable window for surgical intervention to enhance outcomes in rectal cancer patients.