Prognostic Value of Tumor Regression Grade Combined with Pathological Lymph Node Status in Initially Node-Positive Rectal Cancer Treated with Neoadjuvant Chemoradiotherapy.

BACKGROUND

The prognostic value of tumor regression grade (TRG) after neoadjuvant chemoradiotherapy for rectal cancer is inconsistent in the literature. Both TRG and post-therapy lymph node (ypN) status could reflect the efficacy of neoadjuvant therapy. Here, we explored whether TRG combined with ypN status could be a prognostic factor for MRI-based lymph node-positive (cN+) rectal cancer following neoadjuvant chemoradiotherapy.

METHODS

671 cN + rectal cancer patients who received neoadjuvant chemoradiotherapy followed by radical resection were enrolled. Patients were innovatively divided into three groups based on TRG and ypN status: TRG0-1N0, TRG2-3N0 or TRG0-1N+, TRG2-3N+. Kaplan-Meier method and log-rank test were used to compare the disease-free survival (DFS) and overall survival (OS) among three groups. Univariate and multivariate analyses were performed to explore the prognostic value of the modified TRG in cN + rectal cancer following neoadjuvant chemoradiotherapy.

RESULTS

The mean duration of follow-up was 30.4 months. Significant survival differences were observed among the three groups. The 3-year DFS were 83.0%, 69.2% and 55.9%, respectively. The 5-year OS were 83.5%, 80.4% and 57.8%, respectively. TRG combined with ypN status was an independent predictor for both DFS and OS in multivariate analysis.

CONCLUSION

TRG combined with ypN status is a novel prognostic factor in cN + rectal cancer following neoadjuvant chemoradiotherapy, which assists clinicians make appropriate decisions regarding postoperative treatment and surveillance.