Hong N, et al. – Tamoxifen (TMX) and aromatase inhibitors (AIs) were compared for their effects on the risk of fatty liver in conjunction with longitudinal changes in the serum lipid parameters. In postmenopausal women with early breast cancer, TMX independently increased the 5–year risk of newly developed fatty liver compared with AI. In view of this outcome, experts encouraged for considering the risk of fatty liver as a different adverse event profile between AI and TMX, particularly in patients with obesity, high triglycerides (TGs) and low high–density lipoprotein cholesterol (HDL–C).

Methods

• In this study, among 1203 subjects who were taking adjuvant TMX or AI (anastrozole or letrozole) without fatty liver at baseline, those taking TMX or AI were 1:1 matched on the propensity score.
• Newly developed fatty liver detected on annual liver ultrasonography was the primary outcome.

Results

• 62 cases of fatty liver in the TMX group and 41 cases in the AI group were detected in a total of 987.4 person-years, among 328 matched subjects (mean age 53.5 years, body mass index 22.9 kg/m2).
• Results revealed higher incidence rate of fatty liver in the TMX group than in the AI group (128.7 versus 81.1 per 1000 person-years, P = 0.021), particularly within the first 2 years of therapy.
• As compared with AI independent of obesity and cholesterol level, TMX was associated with an increased 5-year risk of newly developed fatty liver (adjusted hazard ratio 1.61, P = 0.030).
• Data displayed higher triglycerides (TGs) and lower high-density lipoprotein cholesterol (HDL-C) level in subjects who developed fatty liver at baseline than those without, which was sustained during follow-up despite the serum cholesterol–lowering effect of TMX.