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.