The clinical significance of venous invasion in cancer of the stomach.

Specimens from 235 surgically treated cases of gastric cancer were examined for venous invasion in order to investigate its clinical significance. A total of 87 (37.0 per cent) cases showed histologic evidence of venous invasion, with the incidence being 48.3 per cent of 180 cases, after the exclusion of 55 cases where cancerous invasion was limited to the mucosa. The frequency of venous invasion varied with the gross type of tumor, the depth of penetration and the degree of differentiation, being highest in tumors of type 2 and moderately differentiated adenocarcinoma. It increased proportionately depending upon the depth of penetration and the incidence increased in cases where there was evident lymphatic invasion or lymph node metastasis. The long term survival rate significantly decreased in patients with venous invasion when compared to those without it. In this report, we also discuss the marked difference in the incidence of liver metastasis between gastric and colorectal carcinomas in relation to venous invasion of the primary tumor. Double staining with Victoria blue and hematoxylin-eosin for elastic fibers proved useful for detecting venous invasion in the carcinomatous tissue, though endothelial markers have great specificity for differentiating small veins from lymphatics.