Prognostic significance of total lymph node number in patients with T1-4N0M0 colorectal cancer.

BACKGROUND/AIMS: The presence of lymph node metastases is the main prognostic factor in patients with colorectal cancer. Controversy exits relating to the minimum number of lymph nodes to be harvested for accurate staging in patients classified as stage I and II. The purpose of this study was to define a cut-off value for the number of lymph nodes examined and determine if this minimum number could have any impact on prognosis of node negative patients. METHODOLOGY: A total of 301 T1-4N0M0 colorectal cancer patients were reviewed. The clinical and pathological factors considered in statistical analysis were age, gender, tumor location, depth of invasion, differentiation and the number of examined lymph nodes. RESULTS: The median number of harvested lymph nodes was 10 and the 5-year overall survival rate was 62%. Univariate analysis revealed that patients with well differentiated, right-sided, T1-2 tumors and those with more than 11 nodes examined had improved survival compared to their counterparts. In Cox regression analysis, the same variables except tumor location independently affected the prognosis, where the number of lymph nodes recovered showed the highest significance (p=0.0008; RR: 2.8; 95% CI: 1.6-5.2). CONCLUSIONS: Patients classified as T1-4N0M0 colorectal carcinoma with more than 11 lymph nodes examined may be considered as more accurately staged and have better prognosis than those with lower number of lymph nodes recovered.