Combined hepatocellular cholangiocarcinomas; analysis of a large database

Abstract

Aim: Combined hepatocellular cholangiocarcinoma (combined tumor) has been described as either a variant of hepatoma or a variant of cholangiocarcinoma. Prior studies evaluated fewer than 50 patients with combined tumors, precluding multivariate analyses. Posited was the notion that analysis of a large database would yield more definite answers.

Methods: This study used SEER (Surveillance, Epidemiology, and End Results Program of the National Cancer Institute) to analyze 282 combined tumors, 2,035 intrahepatic cholangiocarcinomas, and 19,336 hepatomas between the years 1973-2003. Multinomial logit regression calculated point estimates and 95% confidence intervals (c.i.) for relative risk (rr). Cox regression calculated point estimates and 95% confidence intervals (c.i.) for hazard ratios (ĥ).

Results: Men less often had cholangiocarcinomas than they had combined tumors (rr = 0.63, c.i. = 0.49-0.81). Hepatomas less often than combined tumors presented with distant spread (rr = 0.56, c.i. = 0.43-0.72). Men (rr = 1.50, c.i. = 1.17-1.93) and patients with a known Asian or Pacific birthplace (rr = 2.36, c.i. = 1.56-3.56) more often had hepatomas than they had combined tumors. Among patients not known to have an Asian/Pacific birthplace, a diagnosis of cholangiocarcinoma (ĥ = 0.72, c.i. = 0.63-0.82) or hepatoma (ĥ = 0.75, c.i. = 0.66-0.86) provided a better prognosis than did a diagnosis of combined tumor.

Conclusion: Combined tumors differ from hepatomas and cholangiocarcinomas in terms of distribution and survival patterns in the population; they should be considered neither cholangiocarcinomas nor hepatomas.

Keywords: cholangiocarcinoma; combined hepatocellular cholangiocarcinoma; hepatoma; multinomial logit; survival analysis.