The Role of MRI in the Preoperative Staging of Rectal Cancer: Ten-year Experience from a Single Tertiary Center

Background/Aim: Accurate preoperative staging of rectal cancer (CRC) guides treatment decisions, particularly regarding neoadjuvant chemoradiotherapy. Although magnetic resonance imaging (MRI) is recommended for local staging, questions persist regarding whether T stage or circumferential resection margin (CRM) involvement is the stronger predictor of treatment necessity. This study evaluated ten years of institutional experience to determine whether MRI-based CRM assessment provides superior prognostic guidance compared to tumor-node-metastasis (TNM) staging alone. Patients and Methods: Between March 2014 and July 2023, 659 patients underwent surgery for histologically confirmed rectal adenocarcinoma; 258 received preoperative MRI and computed tomography (CT) imaging. After applying exclusion criteria (neoadjuvant therapy prior to surgery, transanal endoscopic procedures, patient refusal, contraindications), 114 patients undergoing primary surgical resection comprised the study cohort. MRI- and CT-derived T and N stages and CRM involvement were compared with definitive histopathological findings using chi-squared, Fisher’s exact, independent t-tests, Mann-Whitney U-tests, and diagnostic accuracy calculations. Results: MRI correctly predicted pathological T (pT) stage in 47.4% of cases versus CT in 48.2% (p=0.895), indicating no significant difference. CT more frequently underestimated T stage (33.3%), whereas MRI more often overestimated (36.8%, p