Delaying surgery after neoadjuvant chemoradiotherapy improves prognosis of rectal cancer

To investigate the prognostic effect of a delayed interval between neoadjuvant chemoradiotherapy (CRT) and surgery in locally advanced rectal cancer.

We evaluated 87 patients with locally advanced mid- or distal rectal cancer undergoing total mesorectal excision following an interval period after neoadjuvant CRT at Şişli Hamidiye Etfal Training and Research Hospital, Istanbul between January 2009 and January 2014. Patients were divided into two groups according to the interval before surgery: < 8 wk (group I) and ≥ 8 wk (group II). Data related to patients, cancer characteristics and pathological examination were collected and analyzed.

When the distribution of timing between group I (n = 45) and group II (n = 42) was viewed, comparison of interval periods (median ± SD) of groups showed a significant difference of as 5 ± 1.28 wk in group I and 10.1 ± 2.2 wk in group II (P < 0.001). The median follow-up period for all patients was 34.5 (9.9-81) mo. group II had significantly higher rates of pathological complete response (pCR) than group I had (19% vs 8.9%, P = 0.002). Rate of tumor regression grade (TRG) poor response was 44.4% in group I and 9.5% in group II (P < 0.002). A poor pathological response was associated with worse disease-free survival (P = 0.009). The interval time did not show any association with local recurrence (P = 0.79).

Delaying the neoadjuvant CRT-surgery interval may provide nodal down-staging, improve pCR rate, and decrease the rate of TRG poor response.