Impact of interval between neoadjuvant chemoradiotherapy and surgery for rectal cancer on surgical and oncologic outcome.

Background: The aim of this study was to evaluate the effect of a longer interval between long-course neoadjuvant chemoradiotherapy and surgery on surgical and oncologic outcome.

Methods: A total of 233 consecutive patients with clinical stage II and III rectal cancer were divided into 2 groups according to the neoadjuvant-surgery interval: short-interval group (≤ 7 weeks, n = 111), and long-interval group (>7 weeks, n = 122). Data on neoadjuvant-surgery interval, operative time, perioperative complications, final pathology, disease recurrence, and mortality were prospectively collected and analyzed.

Results: The two groups were comparable in terms of demographics, tumor, and treatment characteristics. Operative time and perioperative complications were not influenced by a longer interval. Patients in the long-interval group had a significantly higher pathologic complete response (pCR) rate (27.1% vs. 15.3%, P = 0.029), and a decreased rate of circumferential resection margin involvement (1.6% vs. 8.1%, P = 0.020). After a median follow-up of 42 months (range 6-90 months), the 3-year local recurrence rate was 12.9% in the short-interval group versus 4.8% in the long-interval group (P = 0.025).

Conclusions: A neoadjuvant-surgery interval >7 weeks is safe and is associated with a higher rate of pCR and R0 resection, and decreased local recurrence.