No Bones About It: Adjuvant Biophosphonate Meta-Analysis – Overall Survival Benefit in Postmenopausal Patients
SABCS 2013 audience members were treated to an excellent Thursday morning plenary overview of adjuvant bisphosphonate therapy in breast cancer1 by Dr. Michael Gnant followed by the long awaited EBCTCG adjuvant bisphosphonate meta-analysis2 presented by Dr. Robert Coleman in the afternoon.
SABCS 2013 S4-07: Effects of BP Treatment on Recurrence and Cause-Specific Mortality in Women With Early Breast Cancer: A Meta-Analysis of Individual Patient Data From Randomised Trials. R. Coleman et al.
Background: Disseminated tumour cells can remain dormant in the bone marrow for years prior to subsequent activation and the development of overt metastases. Bisphosphonates (BP) have profound effects on bone physiology and could potentially modify the metastatic disease process. Variable outcomes in terms of disease recurrence have been reported, with efficacy apparently influenced by menopausal status.
Methods: We sought individual patient data for meta-analysis from 41 randomised trials that compared BP to no BP (placebo or open control). Primary outcomes were time to recurrence, time to first distant recurrence and breast cancer mortality. Predefined subgroup comparisons were of type of BP (amino-/non-amino), duration and schedule of BP treatment, menopausal status, age, ER status, concomitant chemotherapy and site of distant recurrence (bone/other).
Results: Data on 17,751 women (75% of 23,573 randomised in relevant trials) have so far been received, with around 3,300 breast cancer recurrences and 2,500 deaths. Effects on breast cancer mortality, recurrence and bone metastases for 17,016 women in the locked database and for 10,540 who were postmenopausal are shown below.