Delayed versus immediate surgery following short-course neoadjuvant radiotherapy in resectable (T3N0/N+) rectal cancer

Abstract

Purpose Preoperative short-course radiotherapy (SCRT) followed by surgery has shown advantage over surgery alone in patients with resectable rectal carcinoma (RC); however, the importance of the timing of surgery after SCRT has not been well defined. This study aimed to investigate the effect of this duration on treatment outcomes. Methods Patients who underwent surgery after SCRT (25 Gy/500 cGy/daily/5fr, monday-friday) for resectable and infraperitoneal rectal adenocarcinoma (T3N0/(+)) were included into the study. Patients were divided into two groups in terms of the timing of surgery: delayed surgery (>4 weeks) or immediate surgery (<4 weeks). Results A hundred and thirty-six patients were included in the study. Median time between RT and surgery was 4 +/- 5.7 (1-58) weeks, where 68% (n = 93) patients underwent delayed surgery (>= 4 weeks). The two groups did not differ in terms of surgical margin positivity, pathological tumor regression, N downstaging, or T downstaging (p > 0.05 for all). However, the number of positive lymph nodes was higher in the immediate surgery group [median 3 (0-18) vs. 1 (0-17), p = 0.009]. Median follow-up time was 36 +/- 9 (6-93) months. Delayed surgery group had significantly longer mean overall survival (p = 0.038); however, the two groups did not differ in terms of local recurrence, mean time to local recurrence, or mean disease-free survival. Conclusions Our findings seem to support the benefit of a longer time interval between radiotherapy and surgery after short-course neoadjuvant radiotherapy in resectable rectal cancer in terms of overall survival. However, there is a need to better define patient characteristics that might benefit from delayed surgery.