Purpose: Preoperative neoadjuvant therapy is standard before surgery for locally advanced rectal cancer in current clinical treatment. However, patients with the same clinical TNM stage before treatment vary in clinical outcomes. More and more studies noted that pathological findings after preoperative neoadjuvant therapy are better prognostic factors to determine prognosis than clinical TNM stage in patients with locally advanced rectal cancer. The purpose of this study is to develop and validate models based on pathological findings to predict overall survival (OS) and disease-free survival (DFS).
Patients and Methods: A total of 3026 patients from two hospitals were included. The endpoint was OS and DFS. Significant predictors of OS on multivariate analysis were used to establish the nomogram.
Results: The Harrell’s C index for OS prediction was 0.72 (95% confidence interval [CI], 0.68 to 0.77) in the training cohort, 0.66 (95% CI, 0.60 to 0.72) and 0.68 (95% CI, 0.64 to 0.73) in the internal and external validation cohorts. Using this nomogram, high- and low-risk groups for OS were defined in the training cohort. The 3-year OS was 78.1% (95% CI: 72.4– 84.2%) for the high-risk group and 95% (95% CI: 93.6– 96.5%) in the low-risk group (HR: 4.42, 95% CI: 3.22– 6.05; P< 0.001). This finding was also applied in the two external cohorts. Similarly, a nomogram that contained the same indices was developed and validated to predict for DFS.
Conclusion: Nomograms based on pathological findings are a reliable tool to predict 3-year OS and DFS rate in patients with locally advanced rectal cancer.
Keywords: locally advanced rectal cancer, nomogram, pathological findings, overall survival, disease-free survival