Abstract
525 Background: Risedronate is used for preventing postmenopausal osteoporosis. Its effect in preventing bone loss in premenopausal women undergoing chemotherapy for BC is unknown. Methods: A randomized, placebo controlled, double blind phase III trial assessed the effect of risedronate in premenopausal women undergoing adjuvant chemotherapy for BC (Stage I-IIIB). Women ≥ 18 years were randomized to risedronate 35 mg weekly or placebo for 1 year; all pts received daily calcium 600 mg/vitamin D 400 units. Chemotherapy regimens included anthracyclines, taxanes, cyclophosphamide, methotrexate, or fluorouracil, with a mean duration of 146 days. Patients were stratified by tamoxifen, taxane use, time from last menses, and age. The primary endpoint was the change in lumbar spine bone mineral density (BMD) from baseline to 1 year. A two-sided two-sample t-test with 200 patients had 80% power to detect a 5% difference in the change over 12 months between treatment groups with a 5% Type I error rate. Linear regression modeling of the BMD at 1 year was used to adjust for covariates. Results: 216 women enrolled. 154 completed treatment. There was no difference in mean BMD change at 1 year vs. placebo (Table) and no difference in success rates (increase in BMD) between arms (p =0.43). Regression modeling confirmed no treatment effect (p=0.13) when controlled for baseline BMD and tamoxifen. No significant differences in adverse events were noted, except that arthralgias and chest pain were worse with placebo p=0.04). Conclusions: Risedronate did not prevent bone loss in premenopausal women undergoing adjuvant chemotherapy for BC. We gratefully acknowledge support from Aventis, Proctor & Gamble, and NCCTG (NIH CA25224) for this study. Changes in BMD from Baseline Measurement (g/cm) Risedronate Placebo P Value L Total - change at 1 year −0.06 −0.07 0.324 Femoral neck - change at 1 year −0.03 −0.03 0.364 Total hip - change at 1 year −0.03 −0.04 0.453 Author Disclosure Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Expert Testimony Other Remuneration Aventis
Published Version
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