Incidence and survival trends for primary carcinomas of the liver in the pediatric and younger adult population: Fibrolamellar carcinoma, hepatocellular carcinoma, and cholangiocarcinoma.

e16251 Background: Multiple studies have shown a rise in the incidence of carcinoma among the pediatric and younger adult populations, including breast, kidney, and pancreas carcinomas. In contrast, there is little data on changes in the incidence of liver cancer in the pediatric and young adult population for primary liver carcinomas, especially for rare liver cancer such as fibrolamellar carcinoma and cholangiocarcinoma. This study determines the incidence and mortality of primary liver carcinomas in the pediatric and young adult population. Methods: Patients diagnosed with cholangiocarcinoma, fibrolamellar carcinoma, and hepatocellular carcinoma were selected from the National Cancer Database (NCDB) using histology codes 8160, 8171, and 8170. United States census data stratified by age groups from 2000 – 2022 was also collected. Years 2001 – 2009, for which there was no yearly census data, was estimated. Yearly incidence rates per age group were calculated, with ages of 0-9 years classified as the pediatric population and 11-35 years as the younger adult population. Linear regression models were made. Data was analyzed using R version 4.4.2 with α = 0.05. Results: There was a significant increase in the incidence of hepatocellular carcinoma among the younger adults from 2002 – 2022 (β = 0.0014, p = 0.00315), with a significant decrease in survival (β = -4.478, p = 0.00216), but no significant change in the incidence or survival in the pediatric population. Conversely, there was no significant increase in the incidence of fibrolamellar carcinoma among the younger adults, but there was a slight significant increase in incidence for the pediatric population (β = 0.0002, p = 0.04175) as well as a significant decrease in survival outcomes (β = -1.2990, p = 0.02548). While there was no incidence change in fibrolamellar carcinoma in the younger adult population, there was a significant decline in mortality (β = -2.342, p < 0.0001). Finally, there was no significant change in incidence for cholangiocarcinoma among either the pediatric or young adult population. Conclusions: Together, these data show hepatocellular carcinoma and fibrolamellar carcinoma are increasing in the younger population, pointing towards the need for further study.