Pathological Tumor–Nodal Response Patterns After Neoadjuvant Treatment for Rectal Cancer: Prognostic Impact of Residual ypN-Positive Disease

Background/Objectives: Pathological response to neoadjuvant treatment in rectal cancer may differ between the primary tumor and regional lymph nodes, and the prognostic implications of this discordance remain incompletely defined. We evaluated oncological outcomes according to combined pathological tumor–nodal response patterns, with particular emphasis on complete primary-tumor regression with residual ypN-positive disease.

Methods

A total of 215 patients with nonmetastatic rectal adenocarcinoma who received neoadjuvant treatment followed by curative-intent resection were retrospectively analyzed. Patients were classified as ypT0N0 (n = 34), ypT0N+ (n = 13), residual primary tumor/ypN0 (n = 119), or residual primary tumor/ypN+ (n = 49). The primary endpoint was time to recurrence (TTR). Kaplan–Meier, Cox, Firth penalized Cox, competing-risk, and sensitivity analyses were performed.