Role of reproductive factors in hepatocellular carcinoma: Impact on hepatitis B- and C-related risk.

Hepatocellular carcinoma (HCC) is more prevalent in men than in women. Estrogen may play some role in the development of HCC. We conducted a multicenter case-control study to evaluate the effects of reproductive factors on HCC risk, and to assess whether the association between each factor and HCC differs between hepatitis B surface antigen (HBsAg)-positive and -negative women, in which hepatitis C virus (HCV) is the major cause of HCC. The study included 218 women with HCC and 729 control women selected from nonbiological and first-degree female relatives of patients with HCC. The risk of HCC was inversely related to the number of full-term pregnancies (FTP) (P(trend) =.0216) and age at natural menopause (P(trend) =.0251 among women aged 45-55 without prior surgical menopause). Oophorectomy at age <or=50 during premenopausal years was also a risk factor (multivariate-adjusted OR, 2.57; 95% CI, 1.42-4.63). Use of hormone replacement therapy (HRT) (multivariate-adjusted OR, 0.46; 95% CI, 0.27-0.79) was associated with a lower risk of HCC, and there was a trend in the risk with increasing duration of HRT (P(trend) = 0.0013). All reproductive factors had a similar impact on HBsAg-positive and -negative women except for an early menarche (<or=12 vs. >or=16 years), which increased HCC risk in HBsAg carriers (multivariate-adjusted OR, 6.96; 95% CI, 2.52-19.18) but posed no increased risk in noncarriers (P(interaction) =.0053). In conclusion, increased exposure to estrogen during adulthood may provide a protective effect against HCC. Nevertheless, an early menarche, which results in early estrogen exposure, does not confer protection for HBsAg carriers.