Impact of the total number of harvested lymph nodes after colon cancer resections on survival in patients without involved lymph node.

BACKGROUND The total number of harvested lymph nodes has been demonstrated to be of prognostic significance for colon cancer. Differences can occur in the total number of harvested lymph nodes between different specialists (surgeons and pathologists). OBJECTIVE The aim of this study was to analyse if, in our centre, the number of analysed lymph nodes in patients with colon cancer that are classified as pN0 is also related to survival. MATERIAL AND METHODS A retrospective study was designed, where 148 patients with colon adenocarcinoma (pN0 of TNM classification) who underwent elective surgery between 1 January 1995 and 31 December 2001, with curative intent were included. Three groups were created according to the number of analysed lymph nodes ( < 7, 7-14, > 14 lymph nodes). For survival analysis the Kaplan-Meier and CUSUM curves methods were used. RESULTS The total number of analysed lymph nodes was 1,493 (mean 10.1 lymph nodes per patient). The rate of 5-years survival was 63.0% in the group with < 7 lymph nodes; 7-14 lymph nodes: 80.6% and those with > 14 lymph nodes: 91.8% (p < 0.01). Prognostic significance was also present for multivariate analysis. CONCLUSION In our centre, harvesting a larger number of lymph nodes is related to improved rates of 5-years survival for patients with colon cancer staged as pN0. It seems reasonable to recommend obtaining as many lymph nodes as possible, and not to establish a minimum number of lymph nodes to be harvested.