1 Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center.
2 Division of Cancer Control and Population Sciences, UPMC Hillman Cancer Center firstname.lastname@example.org.
3 Cancer Control and Population Sciences, University of Pittsburgh Cancer Institute.
4 Duke NUS Graduate Medical School.
5 Health Services and Systems Research, Duke-NUS Medical School.
BACKGROUND: Intake of tomato and/or lycopene has been found to be associated with reduced risk of several cancer types, but there is no report on the association with risk of hepatocellular carcinoma (HCC).
METHODS: The associations of tomato and lycopene consumption with risk of HCC were examined in the Singapore Chinese Health Study, a prospective cohort of 63,257 Chinese aged 45-74 years at enrollment from 1993 to 1998. Usual diet was assessed using a validated semi-quantitative food frequency questionnaire. Incident HCC cases were ascertained through linkage with the nationwide Singapore Cancer Registry. Cox proportional hazard regression models were used to estimate hazard ratio (HR) and its 95% confidence interval (CI) of HCC with the consumption of tomato and lycopene among all cohort participants, and unconditional logistic regression was used to assess the association by hepatitis B surface antigen (HBsAg) positivity in a case-control study nested in this cohort.
RESULTS: After a mean follow-up of 17.6 years, 561 incident HCC cases were identified. Higher tomato intake was associated with lower risk of HCC after adjustment for multiple potential confounders (Ptrend<0.001). Compared to the lowest quartile, HRs (95% CIs) of HCC for the 2nd, 3rd, and 4th quartile of tomato intake were 0.70 (0.56-0.88), 0.73 (0.58-0.92), and 0.63 (0.49-0.81). Among HBsAg-negative individuals, the inverse association remained (Ptrend=0.03). There was no association between lycopene intake and HCC risk (Ptrend = 0.54). Conclusions-impact: Tomato intake may offer protection against the development of HCC, particularly among individuals without chronic infection with hepatitis B virus.