Prognostic impact of the number of positive nodes, total number of nodes examined, and depth of the primary tumor for patients in a population-based cohort of 144,744 patients with colon cancer

Impact of positive nodes, the total number of nodes examined, and the depth of primary tumor invasion in a population-based cohort of colon carcinoma. Data from 144,744 patients diagnosed with colon carcinoma between 2004 and 2011 and included in the population-based SEER database were analyzed for five-year relative survival. Each T category is presented separately. The N categories are color-coded as follows: green, N0 (all nodes negative); red, N1a (one positive node); orange, N1b (two or three positive nodes); light blue, N2a (four to six positive nodes); and purple, N2b (seven or more positive nodes). N1c category is not represented because there is not yet a mature cohort in SEER with five-year relative survival. The lines for N category levels spread across the numbers of nodes examined. All patients were free of clinical metastases by surgical and clinical staging; that is, they were in stage groups I to III. Results are mean±SEM of five-year relative survival. Results suggest that the examination of more nodes for a given N category is associated with increasing survival. N0(i+) and N0mi are not included because they were not recorded previously for colorectal carcinoma.