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

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.