The incidence of hepatocellular carcinoma continues to increase rapidly in the United States, with rates increasing the fastest in white men 45 to 54 years of age. These findings are consistent with a true increase and could be explained by consequences of hepatitis C virus acquired during the 1960s and 1970s.

Malignant gastrointestinal stromal tumors rare, but are more common in the older population, men, and Blacks. Risk factors for mortality include older age, Black race, advanced stage, and no surgical intervention.

Background: Diabetes has been associated with an increased risk of hepatocellular carcinoma (HCC) in studies of referred patients. This is the first population based case control study in the USA to examine this association while adjusting for other major risk factors related to HCC. Methods: We used the Surveillance Epidemiology and End-Results Program (SEER)-Medicare linked database to identify patients aged 65 years and older diagnosed with HCC and randomly selected noncancer controls between 1994 and 1999. Only cases and controls with continuous Medicare enrolment for three years prior to the index date were examined. Inpatient and outpatient claims files were searched for diagnostic codes indicative of diabetes, hepatitis C virus (HCV), hepatitis B virus (HBV), alcoholic liver disease, and haemochromatosis. HCC patients without these conditions were categorised as idiopathic. Unadjusted and adjusted odds ratios were calculated in logistic regression analyses. Results: We identified 2061 HCC patients and 6183 non-cancer controls. Compared with non-cancer controls, patients with HCC were male (66% v 36%) and non-White (34% v 18%). The proportion of HCC patients with diabetes (43%) was significantly greater than non-cancer controls (19%). In multiple logistic regression analyses that adjusted for demographics features and other HCC risk factors (HCV, HBV, alcoholic liver disease, and haemochromatosis), diabetes was associated with a threefold increase in the risk of HCC. In a subset of patients without these major risk factors, the adjusted odds ratio for diabetes declined but remained significant (adjusted odds ratio 2.87 (95% confidence interval 2.49-3.30)). A significant positive interaction between HCV and diabetes was detected (p,0.0001). Similar findings persisted in analyses restricted to diabetes recorded between two and three years prior to HCC diagnosis. Conclusions: Diabetes is associated with a 2-3-fold increase in the risk of HCC, regardless of the presence of other major HCC risk factors. Findings from this population based study suggest that diabetes is an independent risk factor for HCC.

Several novel associations with ECC and ICC were identified. HCV infection, chronic nonalcoholic liver disease, and obesity, all of which are increasing in incidence, and smoking were associated only with ICC, suggesting that these conditions might explain the divergent incidence trends of the tumors.