Twenty Years of Modern Rectal Cancer Care in Lithuania: Stage Migration, Evolving Treatment Patterns, and Improved Survival at a Tertiary Referral Centre

Background and Objectives: Rectal cancer management has changed substantially over the past two decades. We evaluated 20-year trends in stage at diagnosis, treatment patterns, and survival at a Lithuanian tertiary referral centre. Materials and Methods: This retrospective cohort study included 839 patients who underwent resection for stage I–III rectal cancer between 2004 and 2023, divided into two periods: 2004–2013 (n = 426) and 2014–2023 (n = 413). Survival was analysed with Kaplan–Meier estimates and Cox proportional hazards regression, truncated at 60 months. Results: Patients in the later cohort were diagnosed at an earlier clinical stage (stage I: 12.6% vs. 2.4%) and more often received neoadjuvant or perioperative therapy (55.2% vs. 37.1%; p < 0.001). Among clinical stage III patients, receipt of neoadjuvant chemoradiotherapy or total neoadjuvant treatment rose from 15.9% to 70.9% (p < 0.001), while pathological complete response among treated patients remained stable (10.8% vs. 10.7%; p = 0.98). Five-year overall survival increased from 64.8% to 71.3% (HR 0.77; 95% CI 0.60–0.99; p = 0.039) and cancer-specific survival from 70.4% to 80.8% (HR 0.60; 95% CI 0.45–0.80; p = 0.0005). The cohort effect persisted after multivariable adjustment for CSS (HR 0.62; 95% CI 0.45–0.85; p = 0.003), with clinical stage explaining only ~13% of the crude effect; stage III sensitivity analysis confirmed the CSS gain (67.9% to 77.3%; p = 0.009). Conclusions: Cancer-specific survival improved substantially and independently of stage migration. The gain coincided with markedly wider and better-targeted delivery of effective neoadjuvant therapy rather than with improved per-patient tumour responsiveness. As an observational comparison of two historical cohorts, this study demonstrates association rather than causation; nonetheless, it provides real-world evidence consistent with the hypothesis that systematic implementation of evidence-based rectal cancer pathways translates into measurable survival benefit.