Prognostic nomograms and risk-stratifying systems for predicting survival in patients with resected pT2-4aN0M0 esophageal carcinoma.

BACKGROUND: According to the National Comprehensive Cancer Network (NCCN) guidelines, surveillance or adjuvant chemoradiation is recommended for patients with completely resected pT2-4aN0M0 esophageal carcinoma (EC). Due to this population's variant prognosis, we developed novel nomograms to define the high-risk patients who may need closer follow-up or even post-operative therapy. METHODS: Cases with resected pT2-4aN0M0 EC from the Surveillance, Epidemiology, and End Results (SEER) database and the Sun Yat-sen University Cancer Center (SYSUCC) were enrolled in the study. The SEER database cases were randomly assigned into the training cohort (SEER-T) and the internal validation cohort (SEER-V). Cases from the SYSUCC served as the external validation cohort (SYSUCC-V). Overall survival (OS) and cancer specific survival (CSS) were compared between groups. Multivariate analyses were applied to identify the prognostic factors. Nomograms and risk-classifying systems were developed. The nomograms' performances were evaluated by concordance index (C-index), calibration plots and decision curve analysis (DCA). RESULTS: A total of 2,441 eligible EC cases (SEER-T, n=839; SEER-V, n=279; SYSUCC-V, n=1,323) were included. Age, sex, chemotherapy, lymph node harvested (LNH) and T stage were identified as the independent predictors for CSS. Regarding OS, it also included the prognostic factor of histology. Nomograms were formulated. For CSS, the C-index was 0.68 [95% confidence interval (CI): 0.66-0.71], 0.67 (95% CI: 0.63-0.71) and 0.61 (95% CI: 0.59-0.63) for the SEER-T, SEER-V, and SYSUCC-V, respectively. For OS, the C-index was 0.69 (95% CI: 0.66-0.72), 0.64 (95% CI: 0.59-0.69) and 0.62 (95% CI: 0.61-0.63) for the SEER-T, SEER-V, and SYSUCC-V, respectively. The calibration curves and DCA showed good performances of the nomograms. In further analyses, risk-classification systems stratified pT2-4aN0M0 EC into low-risk and high-risk subgroup. The OS and CSS curves of these 2 subgroups, in the full analysis set or stratified by TNM stage, histology, T stage and LNH categories, showed significant distinctions. CONCLUSIONS: The novel prognostic nomograms and risk-stratifying systems which separated resected pT2-4aN0M0 esophageal carcinoma patients into the low-risk and high-risk prognostic groups were developed. It may help clinicians estimate individual survival and develop individualized treatment strategies.