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  The Digestive Disease Week 2003 Conference
Orlando, Florida May 17-23, 2003
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Reported by Jules Levin
  Digestive Disease Week Conference 2003. abstract 8. authors: Hashem B El-Serag, Jessica Davila, Nancy Petersen, Houston, TX.
Increasing incidence rates for hepatocellular carcinoma (HCC) were previously reported in the United States, possibly due to chronic HCV infection. However, alternate explanations were diagnostic and/or reclassification bias, and changes in the demographics of the general population. The purpose of this study is to update recent trends in HCC incidence through 1998 and to examine temporal changes in incidence while adjusting for changes in age, gender, ethnicity within geographic regions.
Using information from the Surveillance, Epidemiology, and End Results (SEER) program, we identified all histologically confirmed cases of primary HCC during 1975-98. Age-adjusted incidence rates (AIR) were calculated for consecutive 3-year periods during 1975-98. We used Hierarchical Poisson multivariate regression to examine temporal trends in HCC controlling for changes in age, gender, and race among HCC cases and in the underlying population at risk, while accounting for potential clustering of persons with similar characteristics within geographic regions.
The overall AIR increased from 1.4/100,000 in 1975-77 to 3.0/100,000 in 1996-98; 114% overall increase. There was a 25% increase over the last 3 years of the study. The proportions of patients with liver cancer undergoing microscopic confirmation remained relatively stable over time. The increase in HCC affected most age groups above 40, with the greatest increase between ages 45 and 49. For instance, there was a striking 110% increase during the 1990s in white men (including Hispanic) between 45-49. The AIRs were 2-folds greater in blacks than whites and 2-folds greater in Asians than blacks. However, white men and black women had the greatest percentage increase (31%) in the last time period (1996-98) as compared to 1993-95. The Poisson hierchichal regression model confirmed an almost two fold increase in HCC incidence between 1975 and 1998. A significant interaction between time of diagnosis and race such as that a greater increase in HCC incidence occurred in whites compared to blacks and Asians during more recent time periods.
The authors conclude that the incidence of HCC continues to rapidly increase in the United States. Although this increase has affected most age, gender, ethnic groups, the fastest rising rates have been observed in white men between the ages of 45 and 55. These findings are consistent with a true increase in HCC and could be explained by consequences of HCV acquired earlier in life during the 1960s and 1970s.