Zoledronic Acid May Protect Bones During Breast Cancer

Two studies found drug preserved or increased bone mineral density in premenopausal women

WEDNESDAY, Aug. 20 (HealthDay News) -- Zoledronic acid is associated with preserved bone health in premenopausal women treated for breast cancer, according to the results of two studies, one published online Aug. 18 in the Journal of Clinical Oncology and another published online Aug. 20 in The Lancet Oncology.

Dawn L. Hershman, M.D., of Columbia University in New York City, and colleagues analyzed data from 101 premenopausal women with non-metastatic breast cancer (mean age 42) who were randomized to receive placebo or 4 milligrams of intravenous zoledronic acid every three months for a year. At one year, women in the placebo group had a 4.1 percent decline in bone mineral density in the lumbar spine and a 2.6 percent decline in the total hip, the researchers report. However, bone mineral density stayed stable in women in the treatment group.

In the second study, Michael Gnant, M.D., of the Medical University of Vienna in Austria, and colleagues analyzed data from 404 premenopausal women with endocrine-responsive breast cancer who were treated with endocrine therapy (goserelin and anastrozole or goserelin and tamoxifen) with or without zoledronic acid, given as 4 mg every six months, for three years. Women not receiving zoledronic acid had significant bone loss, and didn't recover their full baseline bone mineral density two years after treatment, the investigators found. However, zoledronic acid prevented bone loss during therapy and increased bone mineral density at five years, they report.

"The results have important implications for the growing number of young breast cancer survivors who will enter menopause early and experience both a prolonged period of estrogen deficiency and an increased long-term risk of osteoporotic fracture. Questions remain regarding the optimal time to initiate bisphosphonates, the appropriate dose and duration of therapy, and the potential for pre-emptive intervention to reduce future fractures," Hershman and colleagues write.

Hershman and a co-author in the first study disclosed research funding from Novartis, which helped fund the study. Gnant and a co-author disclosed financial relationships with Novartis and other companies; Novartis and AstraZeneca supported their study.

Abstract - Hershman
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Abstract - Gnant
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