Bone mineral density in postmenopausal women with hormone receptor-positive breast carcinomas. Preliminary results

Objectives: Several studies suggest an inverse correlation between breast cancer (BC) incidence and osteoporosis, and postmenopausal women with higher T-score values were found to have an increased risk of developing BC. In postmenopausal women the principal origin of serum estradiol is peripheral conversion in the adipose tissue, and thus a high body mass index (BMI) is a well known risk factors for BC. The aim of this study was to evaluate the relationship between BMD, age, and BMI in women with estrogen receptor (ER)-positive BC. Materials/Methods: A series of 19 postmenopausal women with ER-positive infiltrating ductal (ID) breast carcinomas, and 20 age- (62.4±4.0 vs. 62.2±3.9 years, p=0.89) and stage-matched (pT1a-b, N0, M0) postmenopausal patients with ER-negative ID carcinomas were studied. Years since menopause (YSM) (12.4±3.7 vs. 12.3±3.8, p= 0.98) and BMI (24.2±1.1 vs. 24.1±1.1, p=0.94) did not differ between groups. All patients underwent lumbar-spine (L2-L4) BMD measurement. Results: The BMD values were significantly higher in patients with ER-positive BC compared to those with ER-negative ones (0.889±0.015 vs. 0.848±0.022 g/cm2, p<0.01). In ER+ patients, there was a weak inverse correlation between age and BMD (R=−045, p=0.054), and no relationship between BMD and both BMI (R=−0.11, p=0.66) and YSM (R=−0.39, p=0.093), while in ER-negative patients, the BMD values significantly correlated with age (R=−0.49, p=0.026), BMI (R=−051, p=0.019), and YSM (R=−0.48, p=0.031). Conclusions: Our preliminary study confirms that postmenopausal women with ER-positive BC are protected against bone reabsorption, although the biological mechanisms linking BMD and risk of BC are not completely understood.