The number of lymph nodes in colon cancer specimens: what do the numbers really mean?

Aim Stage‐specific survival for colon cancer is improved when more lymph nodes are identified in the surgical specimen. This association is typically attributed to staging effect, but may instead be a surrogate for tumour biology. Method We retrospectively studied a cohort of 48 consecutively treated patients with Stage II colon cancer who underwent complete resection between January 2000 and December 2002. Archived H&E slides were reviewed for lymphocytic infiltration at the leading edge, presence and degree of sinus histiocytosis in the largest node and the presence of lymph node hyperplasia. Results The mean number of lymph nodes identified was 14.1 ± 9.4. T stage was strongly associated with the number of nodes identified (P = 0.01) and the presence of a significant degree of sinus histiocytosis approached statistical significance (P = 0.077). No statistically significant relationship existed between number of lymph nodes in a specimen and tumour location (P = 0.44), grade (P = 0.56) or lymphovascular invasion (P = 0.64). Conclusions T stage is highly associated with the number of nodes found in a colon cancer specimen; a significant degree of sinus histiocytosis may also be predictive. Finding more nodes may be a surrogate for tumour or host‐related factors that impact prognosis.