Analysis of prognostic risk factors in hepatic resection for metastatic colorectal carcinoma with special reference to the surgical margin

Abstract

Liver resection for metastatic colorectal cancer has been established. Nevertheless, it is still controversial whether the surgical margin from the tumour edge to the cut surface of the liver is a significant prognostic factor in hepatic resection for colorectal metastatic liver cancer. To clarify the prognostic risk factors in hepatic resection for colorectal metastasis, univariate and multivariate analyses were performed. Between April 1985 and April 1995, 31 patients underwent curative hepatic resection for metastatic colorectal cancer. The clinical and pathological factors were examined retrospectively. Overall 1-, 3- and 5-year survival rates of the patients were 92, 42 and 39 per cent respectively. Pathological study of 16 resected specimens with a solitary liver tumour revealed hepatic vein invasion by cancer cells in two of 16 cases, portal vein invasion in three, microsatellite lesions in two and biliary tract invasion in six cases. In resected specimens with a solitary tumour measuring less than 4 cm in diameter, one of these factors was observed in only two of nine cases, whereas in specimens with a solitary tumour measuring more than 4 cm in diameter, these factors were observed in six of seven patients (P < 0.05). The distance from the tumour edge to the intrahepatic invasion was less than 10 mm. With univariate analysis, tumour size of 4 cm or more in diameter, an interval of 6 months or less between colorectal and hepatic resection, four or more gross tumours, bilobar involvement and a resection margin from the tumour of less than 10 mm were found to be significant factors indicating a poor prognosis. Cox's proportional hazards model identified a tumour of 4 cm or more in diameter and a resection margin from the tumour of less than 10 mm as poor prognostic factors (P < 0.05). In treating metastatic colorectal cancer to the liver, the surgical margin should be more than 10 mm because occult intrahepatic invasion was always found to be located within 10 mm from the edge of the tumour.