Effect of neoadjuvant therapy regimens on lymph nodes yield in rectal cancer

Pathological nodal staging is relevant to postoperative decision-making and a prognostic marker of cancer survival. This study aimed to assess the effect of different total neoadjuvant therapy (TNT) regimens on lymph node status following total mesorectal excision (TME) for locally advanced rectal cancer (LARC).

A retrospective cohort study of patients treated for node-positive clinical stage 3 LARC with TNT between January 2015 and August 2022. Patients were stratified into induction therapy and consolidation therapy groups. Variables collated included patient demographics, clinical and radiological characteristics of the tumor, and pathology of the resected specimen. Primary outcome was total harvested lymph nodes.

Ninety-seven patients were included (57 [58.8%] males; mean age of 58.5 ± 11.4 years). The induction therapy group included 85 (87.6%) patients while 12 (12.4%) patients received consolidation therapy. A median interquartile range value of 22.00 (5.00-72.00) harvested lymph nodes was recorded for the induction therapy group in comparison to 16.00 (16.00-47.00) in the consolidation therapy arm (p = 0.487). Overall pathological complete response rate was 34%.

Total harvested nodes from resected specimens were marginally lower in the consolidation therapy group. Induction therapy may be preferrable to optimize postoperative specimen staging.