Comparison of stage based oncological results over years based on the colon cancer location using surveillance, epidemiology and final results program (SEER, international cancer institute)

Objective: This study was aimed to determine population-level survival differences for patients undergoing curative surgery for non-metastatic colon cancer on the basis of specific anatomical colon segments and stages for the last two decades. Methods: Patients who underwent curative surgery for non-metastatic colon adenocarcinoma between 2000 and 2019 were identified using the Surveillance, Epidemiology, and End Results (SEER) database. Patients diagnosed with signet-ring cell and mucinous adenocarcinoma were excluded. Seven tumor sites were defined as cecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending and sigmoid colon by the anatomical location. Study time period was divided into four episodes: 2000-2005, 2006-2010, 2010-2015 and 2016-2019. Demographics, clinical and pathologic factors were compared among different colon segments, stages and time periods. Kaplan-Meier survival analysis was conducted for each colon subsite location and stages, and curves were compared with the log-rank test. Results: A total of 195105 patients were identified (Cecum:43855, Ascending colon:39224 Hepatic flexure:9472, Transverse colon:18427, Splenic flexure:6783, Descending colon:12694 and Sigmoid colon:64650) (Stage-1: 58956, Stage-2:68135, Stage-3:68014). Patients with more proximal colon cancer were significantly older, more likely to be female, had higher number of harvested lymph node and nodal positivity. Patients diagnosed with sigmoid and descending colon cancer had higher overall survival rates than more proximal colon cancers. Throughout the study period, three-year and five-year overall survival rates were significantly improved for each colon site and stage. Conclusion: The current study demonstrated improved overall survival rates for all colon sites and stages throughout the years for patients underwent curative surgery for primary non-metastatic colon cancer. Access to early management and improvements in treatment modalities increased overall survival rates throughout the years for each specific colon site and stage. Particularly, awareness and understanding of embryological and surgical planes improve outcomes in colon cancer surgery.