Age at diagnosis is a reported prognostic factor in a variety of solid cancers. In hepatocellular carcinomas (HCCs), several previous studies focused on patient age, but demonstrated inconclusive results on prognosis of young patients. Clinical outcome may differ according to the balance between tumor's own biologic behavior and underlying liver function thus explaining the inconclusive results in previous studies. In this study, we enrolled 282 patients who underwent curative hepatectomy for primary HCCs and had Child Pugh Class A, representing good liver function. Clinicopathologic features were compared between patients aged ≤40 years (young age group) and those aged >40 years (old age group). Thirty-five patients (12.4%) were classified as the young age group and showed larger tumor size (>5cm), higher Edmondson grade, more frequent intrahepatic metastasis and higher alpha-fetoprotein level (>200ng/mL) than old age group. Young age group showed shorter disease specific survival than the old age group. Symptomatic presentation without surveillance was more frequent in the young age group than old age group (45.7% vs. 23.9%). In gene expression profiling analysis, 69 differentially expressed genes between young and old age groups were generated and these genes were mostly associated with cell cycle or cell division. Mitotic rate was significantly higher in HCCs of young patients than those of old patients. In conclusion, HCCs in young patients have distinct clinicopathologic features. Poor prognosis in the young age group could be explained by late detection as well as their own aggressive tumor biology.
Keywords: age; carcinogenesis; cell cycle; liver; oncology.