Evolution of treatment patterns and survival outcomes in non-metastatic rectal cancer: a 15-year real-world single-center analysis

BACKGROUND: Treatment strategies for rectal adenocarcinoma have undergone substantial evolution, driven by advances in surgical techniques, radiotherapy, and systemic therapies. Nonetheless, longitudinal evidence on their real-world adoption and survival trends remains limited. This study investigated temporal trends in patient characteristics, treatment patterns, and outcomes over a 15-year period at a high-volume Korean tertiary center. METHODS: We retrospectively evaluated 6,314 patients with non-metastatic rectal adenocarcinoma who received curative-intent treatment between 2008 and 2022. The study period was divided into five consecutive 3-year intervals to facilitate temporal comparisons. RESULTS: The mean age at diagnosis was 59.4 years, and 62.0% of patients were male. The proportion of clinical T4 tumors increased substantially, from 7.0% to 28.0%, whereas well-differentiated histology declined over time. Minimally invasive surgery rose from 44.5% to 91.0%, driven by the growing adoption of robotic techniques. Neoadjuvant radiotherapy replaced adjuvant radiotherapy as the predominant approach, and capecitabine-based regimens became the most frequent systemic therapy. Across the entire cohort, the 5-year survival rate was 87.6%, with overall survival showing steady improvement across study periods. Relative to the general population, the standardized mortality ratio declined from 5.57 in Period 1 to 3.33 in Period 5, reflecting a measurable reduction in excess mortality. Among patients with locally advanced disease, the highest five-year survival rate was 88.4% in those treated with neoadjuvant therapy followed by surgery. CONCLUSIONS: These findings demonstrate substantial temporal changes in multidisciplinary rectal cancer management, with improved survival observed over time, supporting the continued refinement of multidisciplinary care strategies.