Journal of Clinical Oncology, 2005 ASCO Annual Meeting Proceedings.
Vol 23, No 16S (June 1 Supplement), 2005: 535
© 2005 American Society of Clinical Oncology

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Abstract

Oral clodronate maintains bone mass in women with primary breast cancer

Univ of Sheffield, Sheffield, United Kingdom; Tom Baker Cancer Ctr, Calgary, AB, Canada; Royal Marsden Hosp, Sutton, United Kingdom

535

Background: Breast cancer treatments commonly suppress oestrogen levels, accelerate bone loss and increase osteoporosis risk. As hormone replacement is contraindicated, bisphosphonates provide useful alternatives. Oral clodronate (Bonefos) 1600mg reduced the incidence of skeletal metastases and improved overall survival in a double-blind placebo-controlled study of 1069 women with primary breast cancer. We compared the effects of clodronate on spine and hip bone mineral density (BMD) during treatment and over a further 3-year follow-up period. Methods: BMD was measured by dual x-ray absorptiometry (Hologic QDR1000, Bedford, MA) in 498 women at first diagnosis of breast cancer (n=243 and 255 for clodronate and placebo respectively). The effects were estimated by computing annual rates of change in BMD. Results: Over 2 years of treatment, clodronate significantly increased the mean BMD at the spine and total hip while patients in the placebo group demonstrated a significant decrease at both sites (mean between group differences of +0.016, 95%CI 0.010–0.021g/cm², p<0.0001 for spine and +0.006, 95%CI 0.002–0.010g/cm², p=0.004 for total hip BMD). During the 3 years of follow-up off treatment, a statistically significant but similar decrease in BMD was observed for both clodronate and placebo groups at all sites. The mean between group difference for annual change in spine BMD was –0.001g/cm² (95%CI –0.004–0.001, p=0.22) while that for the total hip was 0g/cm² (95%CI –0.002 –0.002). There were no cases of osteonecrosis. Conclusions: During 2 years of treatment, oral clodronate 1600mg daily has a protective effect on spine and hip bone mass as judged by effects on BMD. After discontinuation, rates of bone loss are similar to, but not greater than, those in placebo-treated women so that at 5 years women previously treated with clodronate still have significantly higher BMD. There may be increased benefit from a longer treatment with clodronate. The optimum duration of treatment with clodronate to protect the skeleton and reduce skeletal metastases remains to be determined.

Author Disclosure

Employment or Leadership Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Berlex/Schering AG, Eli Lilly, Pfizer, Roche AstraZeneca, Berlex/Schering AG, Eli Lilly, Pfizer, Roche, Schering AG Schering AG

Abstract presentation from the 2005 ASCO Annual Meeting

This article has been cited by other articles:

				T. Powles, E. McCroskey, and A. Paterson Oral bisphosphonates as adjuvant therapy for operable breast cancer. Clin. Cancer Res., October 15, 2006; 12(20): 6301s - 6304s. [Abstract] [Full Text] [PDF]