Breast cancer outcome in relation to bone mineral density and bisphosphonate use: a sub-study of the DATA trial.
Breast Cancer Res Treat. 2020 Mar 02;: Authors: van Hellemond IEG, Smorenburg CH, Peer PGM, Swinkels ACP, Seynaeve CM, van der Sangen MJC, Kroep JR, de Graaf H, Honkoop AH, Erdkamp FLG, van den Berkmortel FWPJ, de Roos WK, Linn SC, Imholz ALT, de Boer M, Tjan-Heijnen VCG, Dutch Breast Cancer Research Group (BOOG)
PURPOSE: The phase III DATA study compared 6 and 3 years of adjuvant anastrozole following 2-3 years of tamoxifen in postmenopausal breast cancer patients. This pre-planned side-study assessed the relationship between a reduced bone mineral density (BMD) and distant recurrence-free survival (DRFS), and evaluated the effect of bisphosphonates on DRFS. METHODS: We selected all patients with a BMD measurement within 3 years after randomisation (landmark) without any DRFS events. Kaplan-Meier methods and Cox proportional hazards models were used for analyses. RESULTS: Of 1860 eligible patients, 1142 had a DEXA scan before the landmark. The BMD was normal in 436 (38.2%) and showed osteopenia in 565 (49.5%) and osteoporosis in 141 (12.3%) patients. After a median follow-up of 5.0 years from the landmark, neither osteopenia nor osteoporosis (compared with normal BMD) were associated with DRFS in both the 6-year [osteopenia HR 0.82 (95% CI 0.45-1.49), osteoporosis HR 1.10 (95% CI 0.26-4.67)] and the 3-year arm [osteopenia HR 0.75 (95% CI 0.40-1.42), osteoporosis HR 1.86 (95% CI 0.43-8.01)]. Moreover, bisphosphonate use did not impact DRFS. CONCLUSION: No association was observed between a reduced BMD and DRFS. Neither did we observe an impact of bisphosphonates on DRFS. PMID: 32124136 [PubMed - as supplied by publisher]