Postchemotherapy histological analysis of major intrahepatic vessels for reversal of attachment or invasion by colorectal liver metastases.

Abstract

Although tumor reduction via present-day prehepatectomy chemotherapy can render initially unresectable disease potentially resectable, little is known about the effects of such chemotherapy on liver metastases with known attachment to or invasion of major intrahepatic vessels. We histologically assessed the relationships of liver tumors to major intrahepatic vessels after chemotherapy. In 45 patients who underwent chemotherapy and hepatectomy with pretreatment images showing metastases attached to or invading major intrahepatic vessels, 77 metastases showed attachment to or invasion of 96 vessels. Using postchemotherapy imaging, 11 of 77 metastases (14.3%) appeared separated from 12 of 96 major hepatic vessels (12.5%). Among 83 vessels later examined pathologically, 29 showed direct invasion (35%) and 10 showed attachment (12%). Tumors involved another 9 vessels (11%) that were separated surgically from the tumor and preserved during hepatectomy. Tumor attachment that exceeded 25% of vessel circumferences via imaging after chemotherapy was a factor associated with pathological vascular invasion or attachment according to multivariate analysis (relative risk, 8.449; 95% confidence interval, 1.961-36.415; P = .0042). Liver metastasis attachment to or invasion of major intrahepatic vessels is difficult to eradicate even with otherwise effective chemotherapy.