Aromatase inhibitors versus tamoxifen: serum biochemical profile and imaging studies in Latin American women with ER+ breast cancer

The estimated global incidence of new breast cancer cases is 2.26 million, and 75% of these cases are estrogen receptor positive (ER+). Treatment involves the use of tamoxifen (TX) or aromatase inhibitors (AIs), such as anastrozole and letrozole. The use of these medications is associated with changes in blood cholesterol levels and hepatic steatosis, and TX promotes steatosis more than AIs. Thus, the aim of this study was to determine the effect of TX and AIs on the incidence of hepatic steatosis and on biochemical markers in women with ER+ breast cancer. A cross-sectional study was performed between 2021 and 2024 comprising 38 women with ER+ breast cancer who received TX or AIs in a public hospital in Brazil. Primary data were collected through interviews and secondary data were obtained through medical records, including blood count, lipid profile, liver profile, and ultrasound (US) results. Of the 34 women with ER+ breast cancer, with a mean age of 56.67 ± 12.38 years, those who used AIs had higher LDL (Low-density lipoprotein) (p < 0.001), MCV (Mean corpuscular volume) (p = 0.033), NEU (Segmented neutrophils) (p = 0.044), and ALP (Alkaline phosphatase) (p = 0.019) values than those in the TX Group, all throughout the treatment. The women who had hepatic steatosis at baseline based on US had no changes after treatment. Our results suggest that adjuvant therapy for ER+ breast cancer in women was not associated with an increase in liver enzymes, with the exception of ALP, or the development of hepatic steatosis. However, Ais increased LDL values, a fact that should be considered when choosing the treatment, especially in women with risk factors, such as diabetes mellitus (DM), obesity, and dyslipidemia.