A team of researchers at the Research Institute of the McGill University Health Centre (Montreal, Canada) have demonstrated that bisphosphonates, used to treat osteoporosis in postmenopausal women, could slow bone metastasis in breast cancer patients. The findings were published recently in the Journal of the National Cancer Institute.
Skeletal metastases are life threatening and are known to develop in 70% of breast cancer patients who die from the disease. Oral bisphosphonates are a common medication currently utilized to treat bone deterioration; however, the study is the first of its kind to examine the use of bisphosphonates in skeletal metastasis treatment.
Co-lead author Richard Kremer (director of the Bone and Mineral Unit, McGill University Health Centre, Montreal, Canada), commented: “Our study is novel in that it mainly involved women who were postmenopausal and in whom bone turnover is high due to osteoporosis. We believe that this process results in an environment that is favorable for tumor cell growth and consequent metastasis. We know that bisphosphonates work by slowing down this bone turnover. This will, in turn, make it harder for tumor cells to establish in the bone and may explain why we saw such a decline in metastasis.”
Data from over 21,000 women diagnosed with breast cancer were evaluated in the study, and individuals were divided into groups consisting of those with early-stage, localized breast cancer and those with cancer that had spread to the lymph nodes. The team then carried out an evaluation of the effects of oral bisphosphonates on the occurrence of bone metastases.
The findings demonstrated that women with early stage breast cancer, who had been treated with oral bisphosphonates either before or after diagnosis, had a reduced risk of bone metastasis. This was also seen in women with advanced-stage breast cancer who were treated with bisphosphonates postdiagnosis. In addition, the researchers demonstrated that the longer the duration of bisphosphonate treatment, the greater the reduction of bone metastasis in these breast cancer patients.
Kremer further commented: “An association between bisphophonate use and improved survival was also observed and this merits further investigation. Ours was an epidemiological study, involving a large number of women strengthening the importance of the findings.”
Clinical interventional studies are needed before use of bisphosphonates could be translated into clinical breast cancer practice, and guidelines for such use will have to be developed.
Further understanding of the complex mechanisms of bone metastasis in breast cancer patients will aid future drug development in the field. In the meantime, the findings are the first of their kind to show promise for bisphosphonates in the prevention of progressive cancer metastases, and unveil a potential to further extend lives.