The Impact of Time Interval to Surgery After Neoadjuvant Chemoradiotherapy on Oncological Outcomes: A Long‐Term Follow‐Up Study on Rectal Cancer Patients

Background Neoadjuvant chemoradiotherapy (nCRT) has been shown to improve prognosis in patients with locally advanced rectal cancer (LARC). However, there is still debate regarding the optimal time of surgery following nCRT. Aims This exploratory study aimed to investigate whether there is a difference in oncological outcomes between patients with LARC who undergo surgery within 6 weeks of nCRT and those who wait longer than 6 weeks. Methods and Results This retrospective study included patients with rectal tumors who underwent nCRT followed by laparoscopic surgery during 2011–2020. Based on the time interval, the study participants were divided into two groups: ≤ 6 weeks and > 6 weeks. Receiver Operating Characteristics and Kaplan–Meier survival curves were employed to evaluate the effect of time interval on overall survival (OS) and recurrence‐free survival (RFS). Cox regression analysis was used to identify the prognostic factors of RFS and OS. A total of 175 patients were included in our study with a mean ± SD age of 56.1 ± 12.9 years. The median (interquartile range) follow‐up time was 71 (63) months. There was no difference in demographic and clinical variables between the two groups. Neither pCR, OS, nor RFS was affected by the nCRT‐surgery interval. Multivariable Cox regression analysis showed that patients with ypStage III had a mortality and recurrence hazard of 7.6 and 3.3 times higher than those with pCR ( p < 0.001, p = 0.018, respectively). Additionally, those who underwent abdominoperineal resection (APR) were 5.8 times more at risk of developing recurrence ( p = 0.001). Conclusion The present study revealed that pCR rates, OS, and RFS were not affected by the nCRT‐surgery interval within the cohort studied. In addition, the time interval of more than 6 weeks may be safe, as no substantial difference in postoperative complications was observed between groups. The ypTNM staging was an independent predictor of OS and RFS. Moreover, APR was considered an important prognostic factor for RFS. These findings require further investigation by multicenter, large‐scale studies in the future.