OBJECTIVETo evaluate whether first-degree family history of liver cancer plays a role in liver cancer incidence by prospective evaluation of a patient cohort in Qidong, China over a 20-year period.

METHODSIn May 1992, 708 hepatitis B surface antigen (HBsAg) carriers and 730 HBsAg-negadve controls from Qidong city were enrolled for participation in a prospective cohort study ending in November 2012.Follow-up was carried out every 6 to 12 months, and evaluations included serum assays to measure concentrations of alpha fetoprotein (AFP), HBsAg and alanine aminotransferase (ALT), as well as abdominal ultrasound to assess liver disease.The relationship between baseline (study entry) information of patients with first-degree family history of liver cancer and liver cancer incidence during the two decades of study was statistically assessed.

RESULTSThere were 172 newly diagnosed liver cancer cases in the cohort during 25 753 person-years (py) of follow-up, representing an incidence of 667.88/100 000 py.The incidence rates of liver cancer among participants with or without liver cancer family history were 1 244.36/100 000 py and 509.70/100 000 py respectively, and the between-group difference reached the threshold for statistical significance (P less than 0.01, Relative Risk (RR):2.44, 95% Confidence Interval (CI):1.80-3.31).The incidence rates of liver cancer among participants who had a sibling with liver cancer and participants who had a parent with liver cancer were not significantly different (P > 0.05), but the liver cancer incidence among participants who had a mother with liver cancer was significantly higher than that of participants who had a father with liver cancer (P < 0.05, RR:1.86, 95% CI:1.03-3.36). Among the participants with liver cancer family history, 56.52% (39/69) were diagnosed before 50 years old, and this rate was significantly higher than that of participants without a family history of liver cancer (40.78%, 42/103, P less than 0.05).The incidence rate of liver cancer among the participants who were family history-positive and HBsAg-positive was significantly higher than that of participants who were family history-negative but HBsAg-positive (P < 0.01, RR:1.75, 95% CI:1.29-2.38), and was 59.59 times higher than for participants who were family history-negative and HBsAgnegative.Subgroup analysis of liver cancer incidence among participants who were family history-positive but HBsAg-negative and participants who were family history-negative and HBsAg-negative produced anRR of 2.60, but there was no statistically significant difference between the two subgroups (P > 0.05).At the study's end, the incidence rates of liver cancer for the different subgroups were 32.21% for the family history-positive and HBsAgpositive participants, 19.80% for the family history-negative and HBsAg-positive participants, 1.71% for the family history-positive and HBsAg-negative participants, and 0.65% for the family history-negative and HBsAg-negative participants.

CONCLUSIONFirst-degree family history of liver cancer is a risk factor of liver cancer in Chinese patients from Qidong, and exhibits synergism with HBsAg-positivity for incidence of liver cancer.