“These data provide support for the hypothesis that preventive therapy with an aromatase inhibitor is likely to be most effective for [patients] with higher estradiol–SHBG ratios and, conversely, of little or no benefit for those with low estradiol–SHBG ratios,” according to the study authors.
Routinely measuring serum hormones in postmenopausal individuals appears to be inexpensive and may assist practices in identifying those who may benefit most from treatment with an aromatase inhibitor for the prevention of breast cancer, according to findings from a case-control study using data from the IBIS-II prevention trial (ISRCTN31488319).
The median estradiol-sex hormone binding globulin (SHBG) ratio was 0.36 (IQR, 0.20-0.74) among patients with breast cancer and 0.28 (IQR, 0.17-0.62) among controls. Additionally, the median testosterone-SHBG ratio was 0.013 (IQR, 0.090-0.019) and 0.011 (IQR, 0.008-0.017) for cases and controls, respectively.
Investigators noted a relative benefit of 0.49 (95% CI, 0.32-0.62; P <.0001) with anastrozole compared with placebo. Data showed an increase in the risk of breast cancer with rising estradiol-SHBG ratios in the placebo group (trend per quartile, 1.25; 95% CI,…
