MRI versus histopathology in EMVI detection for rectal cancer: prognostic relevance and survival outcomes

OBJECTIVES: To evaluate the diagnostic accuracy of magnetic resonance imaging (MRI) compared to histopathology for detecting extramural venous invasion (EMVI) in rectal cancer, and to assess their prognostic value for long-term recurrence-free survival (RFS) and overall survival (OS). MATERIALS AND METHODS: In a prospective cohort of 150 patients with biopsy-confirmed rectal adenocarcinoma, EMVI was assessed via high-resolution 1.5-T MRI and histopathological examination. Interobserver agreement, clinical correlations, and survival outcomes were analyzed. Kaplan-Meier and Cox regression analyses were used to evaluate recurrence-free survival (RFS) and overall survival (OS). RESULTS: mrEMVI was detected in 52.7% of patients and showed good interobserver agreement (κ = 0.68). pEMVI was confirmed in 45.9% of surgical cases, with fair agreement with mrEMVI (κ = 0.40). mrEMVI was significantly associated with advanced tumor stage, larger tumor volume, synchronous metastases, and elevated CEA levels. mrEMVI positivity predicted poorer RFS (HR 5.22, p < 0.001) and OS (HR 3.40, p = 0.01), while pEMVI showed no significant prognostic value. CONCLUSION: mrEMVI is a more reliable imaging biomarker strongly correlated with long-term oncologic events compared to histopathological EMVI. KEY POINTS: Question Reliable preoperative markers are lacking for accurate EMVI detection in rectal cancer, creating uncertainty in risk stratification and treatment decisions due to inconsistent MRI-pathology concordance. Findings mrEMVI showed strong prognostic value for recurrence and survival, whereas pEMVI did not, and MRI offered higher reliability and reproducibility than histopathology. Clinical relevance Identifying mrEMVI preoperatively enables more accurate risk stratification, helping clinicians tailor treatment intensity and potentially improve survival, while highlighting MRI as a more reliable tool than pathology for guiding management decisions in rectal cancer.