Purpose: 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.
Methods: 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.
Results: 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).
Conclusions: 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.