Lymph Node Harvest and Prognosis in Stage II-III Rectal Cancer in the Era of Total Neoadjuvant Therapy.

Abstract

Current guidelines recommend the examination of a minimum of 12 lymph nodes following rectal cancer resection. However, neoadjuvant therapy is associated with reduced yield, questioning the significance of suboptimal nodal count in the era of total neoadjuvant therapy. To evaluate factors associated with inadequate lymph node count and its impact on survival. Retrospective cohort study. The National Cancer Database. Adult patients with single primary Stage II to III rectal adenocarcinoma undergoing oncological resection (2006 to 21). Patients were categorized into 6 treatment groups: mesorectal excision alone, neoadjuvant chemotherapy, neoadjuvant chemoradiotherapy with short-course radiation, neoadjuvant chemoradiotherapy with long-course radiation, total neoadjuvant therapy with short-course radiation, and total neoadjuvant therapy with long-course radiation. The primary outcome was inadequate lymph node harvest. Secondary outcome was overall survival. Of the 44,847 patients, inadequate lymph node harvest occurred in 23%. On multivariable analysis, inadequate lymph node harvest was associated with treatment at community or integrated hospitals, public insurance, lower income area, clinical Stage II disease, poor treatment response, and abdominoperineal resection. Compared with mesorectal excision alone, total neoadjuvant therapy with long-course radiation demonstrated the highest odds of inadequate lymph node harvest (OR 3.94), followed by neoadjuvant chemoradiation with long-course radiation (OR 3.46). Short-course radiation regimens were associated with lower but still increased odds of inadequate lymph node harvest. In the adjusted survival model, inadequate nodal retrieval was independently associated with worse overall survival (hazard ratios 1.19). Retrospective design and lack of granular clinical details. Inadequate lymph node harvest occurred in nearly one-quarter of rectal cancer resections and was associated with patients undergoing long-course radiation-based therapy. Despite treatment-related reduction in lymph node yield, an inadequate count was independently associated with worse prognosis, suggesting that nodal count continues to be a relevant metric in rectal cancer. See Video Abstract.