Objective: To evaluate the impact of downstaging factors on oncologic outcomes in a cohort of patients with rectal cancer after intensified neoadjuvant chemoradiotherapy.
Methods: Clinical and follow-up data of 135 patients with mid-low rectal cancer receiving intensified neoadjuvant chemoradiotherapy in our hospital from 2005 to 2012 were analyzed retrospectively. Tumor stages before chemoradiotherapy (uTNM) and after surgery (ypTNM) were compared. The therapeutic regimen consisted of 25 fractions of totaled 50 Gy radiation and 2-3 cycles of combination chemotherapy with 5-Fu/capecitabine plus oxaliplatin. Association of 3-year disease-free survival (DFS) with T-stage, N-stage and TNM-stage was examined through the comparison of uTNM and ypTNM.
Results: The mean follow-up of 135 patients was 37.1 (12 to 87) months. The 3-year DFS was 85.2%. The 3-year DFS of patients with downstaging of T-stage (n=76) was 90.8%, which was significantly better compared to those without downstaging (n=48, 75.0%, P=0.040). The 3-year DFS of patients with downstaging of N-stage (n=54) was 98.1%, which was n=53, better compared to those without downstaging (significantly 77.4%) and those with progressive disease (n=16, 75.0%) (P=0.009). Multivariate analysis showed downstaging in N-stage was a prognostic factor for DFS (HR=0.793, 95%CI:0.626-1.004, P=0.054).
Conclusions: Patients with pathologic downstaging in T-stage, N-stage and TNM classification after intensified neoadjuvant chemoradiotherapy may improve patient survival. Downstaging in N-stage may be an independent predictor of survival.