Influence of compliance on bone mineral density changes in postmenopausal women with early breast cancer on Anastrozole.

Adjuvant treatment for hormone receptor-positive breast cancer in postmenopausal women with aromatase inhibitors is associated with increased bone loss depending on the compliance to treatment. In this bone substudy, bone mineral density (BMD) was assessed by dual energy X-ray absorptiometry at baseline and after 12- and 24-month treatment in 63 patients receiving Anastrozole as adjuvant treatment for hormone receptor-positive early breast cancer. To minimize the effects of confounders, a matched pair analysis (compliant N = 21, non-compliant N = 21) was performed. Anastrozole treatment in compliant patients leads to a decrease in BMD (g/cm(2)) at lumbar spine and total hip from baseline to 12 and 24 months (-2.57 % P = 0.004; -2.02 % P = 0.05; -2.57 % P = 0.001 and -4.18 % P = 0.003, respectively) compared to non-compliant patients (-1.71 % P = 0.050; -2.00 % P = 0.085; -1.65 % P = 0.055 and -3.20 % P = 0.005, respectively). Anastrozole treatment in compliant patients with breast cancer resulted in a larger, increase in bone loss at 12 and 24 months compared to non-compliant patients. Bone loss stabilized in both groups at the spine from 12- to 24-month treatment, whereas maintained at the total hip.