Non-Restorative Low Anterior Resection Is Associated with Poor Intermediate-Term Oncological Outcomes in MRI-Defined Rectal Cancer

Background: Non-restorative low anterior resection (NRLAR) may result in inferior oncological outcomes compared to restorative low anterior resection (RLAR) and abdominoperineal resection (APR). While NRLAR is often performed when poor functional or technical challenges are anticipated, comprehensive data on its oncological outcomes remain scarce. This study aimed to retrospectively evaluate the intermediate-term oncological outcomes of patients—who underwent RLAR, NRLAR, or APR for primary rectal cancer. Methods: This analysis included all elective NRLAR, RLAR, and APR procedures for primary rectal carcinoma performed across 11 Dutch centers from 2013 to 2020. The primary outcome was 3-year disease-free survival (DFS). Secondary outcomes included 3-year overall survival (OS) and 3-year local recurrence (LR). KaplanMeier survival analysis with log-rank testing and multivariate Cox regression analysis were employed. Results: A total of 253 (12.5%) patients underwent NRLAR, 1109 (55.0%) RLAR, and 656 (32.5%) APR. NRLAR was associated with a lower 3-year DFS (71.4%) versus RLAR (82.0%) and APR (77.4%) (p = 0.003). The 3-year OS was lower for NRLAR (82.9%) versus RLAR (93.5%) and APR (90.2%) (p < 0.001), with a higher 3-year LR rate for NRLAR (8.1%) versus RLAR (3.3%) and APR (4.5%) (p = 0.003). Multivariate Cox regression analyses confirmed NRLAR as an independent predictor for poorer DFS (HR 1.34; 95% CI: 1.01–1.80; p = 0.046), OS (HR 1.57; 95% CI: 1.04–2.36, p = 0.032), and higher LR risk (HR 2.66; 95% CI: 1.53–4.65; p <= 0.001). Conclusions: NRLAR is associated with poorer intermediate-term oncological outcomes. When technically feasible, restorative options should be considered, and prospective studies are required to further investigate causal relationships.