Prognostic significance of post-neoadjuvant MRI-detected extramural venous invasion and tumour deposits in rectal cancer: a systematic review and meta-analysis.

BACKGROUND

Extramural venous invasion (EMVI) and tumour deposits (TDs) are recognised markers of aggressive rectal cancer biology at baseline. However, their prognostic relevance when persisting on post-neoadjuvant MRI remains poorly defined. We performed a systematic review and meta-analysis to evaluate the oncologic impact of persistent MRI-detected EMVI (ymrEMVI) and tumour deposits (ymrTD) and to compare their predictive value with post-treatment nodal status.

METHODS

PubMed, Embase, Web of Science, and Cochrane Library were searched from inception to December 2025. Studies reporting post-neoadjuvant MRI assessment of EMVI and/or TDs with time-to-event outcomes were included. Random-effects meta-analyses generated pooled hazard ratios (HRs) for disease-free survival (DFS), overall survival (OS), distant metastasis-free survival, and local recurrence-free survival.

RESULTS

Seventeen studies encompassing 3932 patients met inclusion criteria. Persistent ymrEMVI was strongly associated with inferior DFS (HR 2.12, 95% CI 1.75-2.56) and OS (HR 2.21, 95% CI 1.63-2.99). ymrTD positivity conferred an even greater adverse impact on DFS (HR 2.85, 95% CI 1.58-5.17) and OS (HR 2.12, 95% CI 1.20-3.74). In contrast, post-treatment nodal status demonstrated inconsistent associations with DFS across studies. These vascular invasion phenotypes showed stronger and more reproducible prognostic value than residual nodal disease.

CONCLUSIONS

Persistent EMVI and tumour deposits on post-neoadjuvant MRI identify a high-risk biological subgroup with markedly inferior survival, outperforming nodal status as prognostic indicators. Incorporation of ymrEMVI and ymrTD into post-treatment risk stratification and trial design is urgently required to guide intensification strategies and personalise rectal cancer management.