The size of retrieved lymph nodes correlates with the number of retrieved lymph nodes and is an independent prognostic factor in patients with stage II colon cancer

PURPOSE: In stage II colon cancer, patients with many retrieved lymph nodes (LNs) have been reported to have better oncological outcomes. We tested the hypothesis that the greater number of retrieved LNs is related to a larger LN size. METHODS: The subjects comprised 320 patients with stage II colon cancer who underwent curative resection. All operations were elective and were performed by the same surgeons. The maximum long axis and short axis diameters of LNs were measured on hematoxylin-eosin-stained specimens. RESULTS: A total of 4,744 LNs were evaluated. The number of retrieved LNs was 14.8 ± 10.1 (mean ± SD). The long axis diameter was 4.8 ± 2.6 mm, with a median value of 4.3 mm, a maximum value of 20.4 mm, and a minimum value of 0.6 mm. The corresponding short axis diameters were 3.4 ± 1.7, 3.0, 15.1, and 0.5 mm, respectively. The highest correlation coefficient for the association with the number of LNs was obtained for the maximum value of the long axis diameter (0.59). Multivariate analysis revealed that age, tumor location, pathological T stage, and the maximum long axis diameter were independent prognostic factors. The number of LNs was not a significant factor. Patients with less than 12 LNs and a maximum long axis diameter of less than 10 mm had significantly poorer outcomes (p < 0.001). CONCLUSION: In patients with stage II colon cancer, the maximum long axis diameter of LNs correlated with the number of LNs and was an independent prognostic factor.