Survival after Curative Treatment for Colon Cancer in Patients Younger than 50 Years of Age Showing a Different Outcome to the Prevailing Literature.

Background: Colorectal cancer is the third most common and second deadliest cancer globally. Increasingly, early‑onset colorectal cancer is diagnosed in those under 50 years, leading to some countries advising screenings from ages 40 or 45 years. The ’position of the tumor, right or left, impacts the characteristics and prognosis of early‑onset colorectal cancer. Objectives: Investigating the 5‑year disease‑free and overall survival and histopathologic nature of left‑ and right‑sided early‑onset colorectal cancer. Design: Retrospective study. Setting: Koc University and VKF American Hospital. Materials (Patients) and Methods: Our population includes patients under 50 years with invasive colon cancer treated in two tertiary Turkish hospitals from 2014 to 2019. Of 178 patients, 74.3% had left‑sided tumors. Sample Size: One hundred and seventy‑eight patients. Main Outcome Measures: Histopathological features of left‑ and right‑sided colorectal tumors, and the 5‑year disease‑free and overall survival rate in patients under 50 years of age. Results: The 5‑year disease‑free survival was higher in right‑sided tumors(78.2% vs. 53.1%), but overallsurvival wassimilar. No significant histopathological differences were noted between left‑ and right‑sided tumors, but right‑sided tumors had more mucinous adenocarcinoma and high microsatellite instability (MSI). Conclusion: Our data did not show a difference in survival between right‑ and left‑sided tumors in the age group <50 years contrary to other published literature. Limitations: Retrospective nature and inclusion of a single center, which usually serves Turkiye population with a higher socioeconomic status. The retrospective nature of the study makes it susceptible to selection bias. The small sample size precludes robust group matching and diminishes the statistical power, increasing the risk of Type II errors. [ABSTRACT FROM AUTHOR]