Aromatase inhibitors are recommended for and widely used as anti-estrogen therapy for postmenopausal women. Numerous studies have shown that these drugs anastrazole (Arimidex), letrozole (Femara), and exemestane (Aromasin) are effective in reducing the risk of a breast cancer recurrence in women with early-stage disease. They also have a well-known side effect: bone loss.
After it became clear that bone loss was a common side effect, many oncologists began to routinely prescribe bisphosphonates drugs that can help prevent bone loss to their patients who were on an AI. The thought was that these drugs, like alendronate (Fosamax) and zoledronic acid (Zometa), would keep women on an AI from developing osteoporosis. It was also thoughtâ€”and some studies had suggested that a bisphosphonate might reduce the risk of a woman developing bone metastases.
But should all women on an AI be taking a bisphosphonate? The answer appears to be no.
In the current issue of the Journal of Clinical Oncology, researchers reported findings from an analysis that explored whether it was more beneficial to give all women on an AI a bisphosphonate; to screen all women (initially and/or annually) and treat those found to have osteoporosis; or to screen all women (initially and/or annually) and treat those found to have osteopenia.
The end result: The most effective approach (health-wise and cost-wise) is to screen women annually and then prescribe a bisphosphonate to the women who are found to have osteoporosis. This is the same approach we use to determine if a healthy woman should start on a bisphosphonate we wait until the problem is seen before giving the drug. (A recent study suggested that annual screening is not recommended for healthy women.)
What about the idea that taking a bisphosphonate will reduce a woman’s risk of developing metastatic disease? This idea made sense, in theory. But, to date, the data haven’t shown any benefit. As the authors of this recent study note, a recent meta-analysis of 13 clinical trials and 7,000 patients found that taking a bisphosphonate did not decrease a woman’s chances of developing bone metastases, having a recurrence, or dying of breast cancer.
This is yet another example of how quickly we often are to jump at ideas that sounds good, rather than wait for the evidence to show us what works.