Résumé
Objective:To evaluate the prognostic significance of neoadjuvant rectal (NAR) score and downstaging depth score (DDS) after neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer (LARC).Methods:Retrospective analysis was performed for 200 patients with LARC (T 3-T 4 and/or N 1-N 2, M 0), who were initially treated in the Cancer Hospital of Chinese Academy of Medical Sciences from 2015 to 2018. All patients had baseline MRI data and received preoperative nCRT and radical resection. All patients received preoperative radiotherapy with a dose of 45-50Gy combined with concurrent capecitabine. The effect of NAR and DDS scores on clinical prognosis was statistically compared. The 3-year disease-free survival (DFS) was calculated using the Kaplan- Meier method and compared by the log- rank test. Cox proportional hazards model was used to perform multivariate survival analysis. The predictive performance for 3-year DFS was calculated using the receiver operating characteristic (ROC) curve. Results:The median follow-up time was 30.5(10.6-54.0) months. In terms of DDS, the 3-year DFS rate was 56.4% in the DDS ≤0 group, significantly lower than 83.0% in the DDS >0 group ( P=0.002). In terms of NAR score, the 3-year DFS rates were 90.1%, 73.8% and 53.6% in NAR score ≤8, 8-16 and>16 groups, respectively ( P<0.001). In the whole cohort, the area under the ROC curve (AUC) of DDS and NAR scores for predicting 3-year DFS were 0.683 and 0.756( P=0.037). In yp0-I stage patients ( n=72), the AUC of DDS and NAR scores for predicting 3-year DFS were 0.762 and 0.569( P=0.032). Conclusions:High DDS and low NAR scores after nCRT indicate good prognosis for patients with LARC. NAR score yields better accuracy than DDS in predicting clinical prognosis, but DDS is significantly better than NAR score in yp0-I stage population.