Grading criteria for venous invasion in thoracic esophageal squamous cell carcinoma

BACKGROUND: Venous invasion (VI) is an adverse prognostic indicator in esophageal squamous cell carcinoma. However, grading criteria for venous invasion in thoracic esophageal squamous cell carcinoma (ESCC) have not been established. METHODS: We enrolled 598 thoracic ESCC patients from 2005 to 2017. We detected the presence of venous invasion using the hematoxylin and eosin (H&E)-staining method and evaluated the VI grade on the basis of the number and maximal size of the involved veins. The degree of VI was classified as either 0, V1, V2, or V3, according to the combination of V-number and V-size. RESULTS: The 1-year, 3-year and 5-year disease-free survival rates were 79.7%, 64.7% and 61.2%, respectively. Multivariate analysis demonstrated that lymphatic invasion (HR: 1.457, 95% CI: 1.058–2.006, p = 0.021), T category (HR: 1.457, 95% CI: 1.058–2.006, p = 0.022), N category (HR: 1.535, 95% CI: 1.276–2.846, p < 0.001), stage (HR: 1.563, 95% CI: 1.235–1.976, p < 0.001) and the degree of venous invasion (HR: 1.526, 95% CI: 1.279–2.822, p < 0.001) were significant indicators of recurrence. The disease-free survival curves were distinguished especially well by the degree of venous invasion in stage III and IV patients. CONCLUSIONS: The present study explored an objective grading criterion for VI and proved the prognostic value of the degree of venous invasion in ESCC. The classification of venous invasion into 4 groups is useful for the differentiation of prognosis in ESCC patients. The prognostic significance of the degree of VI in advanced ESCC patients for recurrence may have to be considered.