The alterations of serum FGF-21 levels, metabolic and body composition in early breast cancer patients receiving adjuvant endocrine therapy.

BACKGROUND

In early breast cancer patients, the effects of hormonal therapy (tamoxifen and aromatase inhibitors) on plasma fibroblast growth factor 21 (FGF-21), lipid levels and body composition have not yet been investigated. Therefore, we aimed to analyze the relationship between FGF-21 and body composition as well as the effects of tamoxifen and aromatase inhibitors on plasma lipid levels, FGF-21, and body composition.

METHODS

A total of 72 patients were treated with either tamoxifen or aromatase inhibitors due to their menopausal status after adjuvant radiotherapy. Each patient was followed-up over a period of 1 year. Changes in body composition and serum lipid profile, glucose and FGF-21 levels were evaluated. We recorded the type of hormonal therapy, body mass index, waist-to-hip ratio, lipid profile, and FGF-21 levels both at the beginning and after 12 months.

RESULTS

There was a statistically significant decrease in serum FGF-21 levels after 12 months of adjuvant endocrine therapy (46 ± 19.21 pg/ml vs. 30.99 ± 13.81 pg/ml, p< 0.001). Total body water (p< 0.001), serum glucose (p= 0.036) and triglyceride levels (p< 0.001) also exhibited a significant decrease. The decreases in total cholesterol and low-density lipoprotein were not statistically significant. Likewise, high-density lipoprotein increased after adjuvant endocrine therapy, although it did not reach statistical significance. The changes in body composition, glucose, lipid profile and FGF-21 were similar in tamoxifen and aromatase inhibitor groups. A positive correlation was found between basal weight, fat mass, fat-free mass and serum FGF-21 levels; however, the correlation was maintained only for the fat-free mass at the 12th month.

CONCLUSION

As part of the present study, we suggest that both tamoxifen and aromatase inhibitors can reduce FGF-21 levels independently of body compositions, and these drugs can provide antihyperlipidemic, antidiabetic and cardio-protective effects. We also recommend that serum FGF-21 level can be utilized as a tumor biomarker in early-stage breast cancer and for monitoring purposes. FGF-21 levels may help physicians estimate prognosis, too. Further studies with larger populations may shed light on the role of FGF-21 in breast cancer.