The Relationship of Lymph Node Evaluation and Colorectal Cancer Survival After Curative Resection: A Multi-Institutional Study

This multicenter retrospective study aimed to clarify whether the number of lymph nodes retrieved influenced staging and survival in colorectal cancer. We evaluated a total of 4538 patients who underwent curative resection for colorectal cancer with stage I, stage II, and stage III. The median number of lymph nodes retrieved was 19. The 5-year actuarial disease-specific survival of colon cancer patients with stage I, stage II, and stage III was 99.0%, 94.1%, and 79.1%, respectively, and that for rectal cancer patients with stage I, stage II, and stage III was 98.2%, 88.3%, and 69.1%, respectively. After adjustment for confounders, the number of lymph nodes retrieved and the number of positive nodes were both significant in prognosis for patients with colon cancer and rectal cancer. Survival improved with an increasing number of nodes in stage II patients. In stage III, patients within strata of retrieval of fewer than 12 nodes with a cutoff based on quartiles had lower discriminative ability (c-index 0.683). Patients who were treated at the hospitals with higher average node counts (> 23.4 nodes) and higher 12-node measure compliance (> 80%) experienced better survival than those treated at the hospitals with lower average node counts for advanced T-stage. This study found that the number of lymph nodes retrieved and the number of positive nodes are both important prognostic factors. At least a 12-node threshold may be supported as a measure to improve a predictive capacity within individual patients and as a quality control parameter of hospital performance.