The evolving role and diagnostic yield of extramural venous invasion in esophageal cancer
The evolving role and diagnostic yield of extramural venous invasion in esophageal cancer
Esophageal cancer (EC) is a high aggressive malignancy with frequent relapse even after curative-intended surgery and multimodal treatment. Extramural venous invasion (EMVI), i.e. tumor cells within large veins beyond the muscularis propria, is a well-established adverse prognostic factor in colorectal cancer, but its role in EC is poorly investigated. This thesis of Lin Zhen systematically evaluates EMVI detection, biology, and treatment responsiveness in EC.
Because larger veins contain distinct components, specialized techniques can enhance EMVI detection. Elastic staining of the outer venous wall proved to be the most accurate and reproducible method, outperforming immunohistochemical markers including ERG, laminin, and α-smooth muscle actin. Using this approach, EMVI was identified in nearly one-third of locally advanced esophageal squamous cell carcinoma (ESCC) patients treated with surgery alone. EMVI independently predicted worse disease-free and overall survival, particularly in node-negative cases.
Biologic analyses of intravascular tumor cells revealed a consistent expression of the hypoxia-induced protein carbonic anhydrase IX (CAIX) across both primary tumors and EMVI tissues. CAIX expression within EMVI was significantly correlated with worse overall survival in node-positive patients, suggesting hypoxia-driven mechanisms contribute to vascular dissemination, representing a possible therapeutic target.
Neoadjuvant chemoradiotherapy (nCRT) was associated with reduced prevalence of EMVI compared with surgery alone, suggesting the effect of nCRT on EMVI tissue. Combined EMVI and lymph-node metastasis emerged as an independent predictor of poor survival after nCRT.
In conclusion, EMVI is a clinically significant and treatment-responsive histopathological feature in EC. Reporting routine elastic staining-based EMVI could improve risk stratification supporting more personalized treatment strategies.