Optimal timing of surgery after neoadjuvant chemoradiation therapy in locally advanced rectal cancer

PURPOSE The optimal time between neoadjuvant chemoradiotherapy (CRT) and surgery for rectal cancer has been debated. This study evaluated the influence of this interval on oncological outcomes. METHODS We compared postoperative complications, pathological downstaging, disease recurrence, and survival in patients with locally advanced rectal cancer who underwent surgical resection <8 weeks (group A, n = 105) to those who had surgery ≥8 weeks (group B, n = 48) after neoadjuvant CRT. RESULTS Of 153 patients, 117 (76.5%) were male and 36 (23.5%) were female. Mean age was 57.8 years (range, 28 to 79 years). There was no difference in the rate of sphincter preserving surgery between the two groups (group A, 82.7% vs. group B, 77.6%; P = 0.509). The longer interval group had decreased postoperative complications, although statistical significance was not reached (group A, 28.8% vs. group B, 14.3%; P = 0.068). A total of 111 (group A, 75 [71.4%] and group B, 36 [75%]) patients were downstaged and 26 (group A, 17 [16.2%] and group B, 9 [18%]) achieved pathological complete response (pCR). There was no significant difference in the pCR rate (P = 0.817). The longer interval group experienced significant improvement in the nodal (N) downstaging rate (group A, 46.7% vs. group B, 66.7%; P = 0.024). The local recurrence (P = 0.279), distant recurrence (P = 0.427), disease-free survival (P = 0.967), and overall survival (P = 0.825) rates were not significantly different. CONCLUSION It is worth delaying surgical resection for 8 weeks or more after completion of CRT as it is safe and is associated with higher nodal downstaging rates.