The impact of tumor location on long-term survival outcomes in patients with right-sided colon cancer.

Background: The oncologic outcomes of right-sided cancers are generally grouped in studies. We hypothesized that tumor location (cecal vs. ascending vs. hepatic flexure) may influence cancer-specific outcomes.

Methods: The Surveillance, Epidemiology, and End Results (SEER) database was queried for patients over 18 with non-metastatic, invasive (American Joint Committee on Cancer stage I-III) right-sided adenocarcinoma of the colon from 1988 to 2014 who underwent partial colectomy. Patients were categorized into groups: (1) cecum (2) ascending colon (3) hepatic flexure. Demographic, clinical and pathologic factors were compared between groups. Disease-specific and overall survival were described using the Kaplan-Meier method and compared using the log-rank test. Multivariate Cox regression analysis determined the independent association of primary tumor location.

Results: We identified 167,450 patients. Mean age was 72.2 ± 12.3 years and 54.9% were female. Of these, 81,611, 66,857, and 18,982 had cecal, ascending colon, and hepatic flexure cancers, respectively. Cecal cancers were associated with a lower number of examined nodes but a higher likelihood of nodal positivity. Cecal cancer patients were significantly older, had larger tumors, and higher tumor stage. On univariate analysis, cecal cancers were associated with poorer disease-specific and overall survival (all p values < 0.001). On multivariate analysis controlling for sex, age, tumor size, number of examined nodes and stage, hepatic flexure cancers were associated with worse disease-specific (HR 1.05) and overall survival (HR 1.03).

Conclusion: Hepatic flexure cancers are associated with worse survival compared to more proximal colon cancers. The cause is likely multifactorial, including biological and technical factors. More aggressive surgical and multimodal therapy may be considered for hepatic flexure colon cancers.