Neoadjuvant rectal score in prognostic prediction of clinical stage III middle-low rectal cancer

Objective: To investigate the effects of downstaging and neoadjuvant rectal (NAR) score on the prognosis of patients with clinical stage III middle-low rectal cancer undergoing preoperative concurrent chemoradiotherapy. Methods: From 2006 to 2014, 195 patients who were admitted to our hospital and diagnosed with clinical stage III middle-low rectal cancer by pelvic magnetic resonance imaging or computed tomography were enrolled. All patients received preoperative radiotherapy with doses of 42-50.4 Gy (median: 50 Gy, 93.8% of patients received doses of ≥ 50 Gy) and concurrent chemotherapy with capecitabine ± oxaliplatin. Total mesorectal (R₀) excision surgery was performed at 4-15 weeks (median: 7 weeks) after concurrent chemoradiotherapy. The effects of downstaging (stage yp0-II) and NAR score (calculated based on cT staging and ypT/N staging) on the prognosis were evaluated. The 3-year disease-free survival (DFS) rate was calculated using the Kaplan-Meier method and analyzed by log-rank test. Results: In all the patients, the median follow-up time was 44 months (6.7-125.5 months); the 3-year DFS rate was 76.8%. Downstaging after preoperative chemoradiotherapy was a significant prognostic factor for the 3-year DFS (92.2% vs. 56.8%, P = 0.000). The median NAR score was 15.0 (0-65.0) in all the patients. Patients with NAR scores of ≤ 15.0 had significantly improved 3-year DFS than those with NAR scores of > 15.0 (90.1% vs. 57.0%, P = 0.001). In patients with downstaging, those with NAR scores of ≤ 8.4 had significantly improved prognosis compared with those with NAR scores of > 8.4 (95.1% vs. 87.5%, P = 0.022). Conclusions: Patients with downstaging after preoperative concurrent chemoradiotherapy for stage c III middle-low rectal cancer have satisfactory prognosis. The NAR score is an effective prognostic predictor. (authors)