Assessment of prognostic factors after primary tumor resection in metastatic colon cancer patients: a Veteran's Affairs Central Cancer Registry (VACCR) analysis, 1995-2008.

BACKGROUND: Resection of the primary tumor in metastatic colon cancer may occur for palliation of bleeding or obstruction despite distant metastases. This study evaluates clinicopathologic features that serve as prognostic markers in those patients with stage IV colon cancer who undergo resection of their primary tumor. METHODS: Retrospective analysis of stage IV colon cancer patients who underwent surgical resection of the primary tumor from 1995 to 2008 was done via the Veteran's Affairs Central Cancer Registry. Age, Charlson co-morbidity index score, extent of metastases, sex, number of lymph nodes examined, lymph node ratio (LNR), type of surgery, use of adjuvant chemotherapy, primary tumor site, and grade were studied with respect to overall survival by using log-rank and Kaplan-Meier analysis. RESULTS: There were 2,625 patients with stage IV colon cancer who had primary tumor resection. Age at diagnosis, Charlson co-morbidity index score, lymph node ratio, and use of chemotherapy were found to be independent predictors of survival by multivariate analysis. CONCLUSION: Clinicopathologic factors such as LNR, use of chemotherapy, age, co-morbidities, site of primary colon tumor, and number of sites of metastasis are all independent predictors of overall survival in patients who undergo primary colon tumor resection in the metastatic setting.