Assessment And Management Of Bone Health In Women Treated With Adjuvant Anastrozole In The Data Study.

534Background: The phase III DATA study (NCT00301457) investigates the efficacy of 6 versus 3 years of adjuvant anastrozole (AI) after an initial 2-3 year treatment with tamoxifen in postmenopausal women with breast cancer. In a planned side study, we assessed patterns of care in detection and treatment of osteopenia/osteoporosis and linear trends over time in bone mineral density (BMD). Methods: BMD measurements and bisphosphonate use in the DATA study were left to the treating physician. We registered all BMD measurements and start of bisphosphonate-use. BMD was measured by a dual-energy x-ray absorptiometry (DEXA) scan of the lumbar spine and/or the hip and transformed to a T-score. Time to osteopenia or osteoporosis was analysed by reverse Kaplan Meier methodology. For the linear trend in BMD T-score, linear mixed models with random effects for patient were used. Results: Of the 1860 eligible patients in the DATA study, 910 (48.9%) had a BMD measurement at the start of anastrozole (baseline). In 417 (...