We can present [findings about bisphosphonates] to our patients as a two-for-one benefit—protecting their bone strength and possibly improving their long-term survival.— Sara Hurvitz, MD
Sara Hurvitz, MD, Director of the Breast Oncology Program at the University of California, Los Angeles, Jonsson Comprehensive Cancer Center, commented that in the United States, a bone mineral density test can help identify candidates for bone-modifying agents.
“We look at women who are going on aromatase inhibitors who have moderate to severe osteopenia or osteoporosis, and the findings might give us more impetus to use these agents,” she said. “We can present this to our patients as a two-for-one benefit—protecting their bone strength and possibly improving their long-term survival.”
However, Dr. Hurvitz acknowledged that fear of osteonecrosis of the jaw is a powerful deterrent for many women. “Even though this is a very low-risk adverse event, it’s significant for patients who develop it, and patients do need to be informed about the risk,” she added.
Mothaffar Rimawi, MD, Medical Director of the Smith Breast Center at Baylor College of Medicine, Houston, agreed that “because of physician and/or patient anxiety over side effects,” bisphosphonates are not used as often as they could be for the prevention of aromatase inhibitor–induced bone loss. “If a patient has a decrease in bone mineral density, you can give it for prevention.”
Mothaffar Rimawi, MD
Press briefing moderator Carlos L. Arteaga, MD, Professor of Medicine and the Donna S. Hall Chair in Breast Cancer at Vanderbilt University School of Medicine, Nashville, also weighed in on the findings. “I think this trial is, in fact, in line with all the other trials of adjuvant bisphosphonates in postmenopausal women,” he said. “The hazard ratio was 0.80, which is similar to what we saw [in postmenopausal patients] in the meta-analysis1—0.86 (P = .002) for recurrence-free survival and 0.82 (P = .002) for breast cancer–specific survival. I think the findings are concordant with what we know, and they are reassuring.”
He added, “Apparently, it doesn’t matter what type of bisphosphonate you choose, although zoledronic acid is much more potent than ibandronate. In the overall analyses, there’s not a huge difference in hazard ratios.”
Carlos L. Arteaga, MD
The concordance of findings for the various classes of bone-modifying agents is good news for patients and providers. As Dr. Hurvitz noted, “[Insurance] coverage also impacts the use of these drugs. We have indications for both zoledronic acid and denosumab (Xgeva), but we have a hard time getting them authorized. We often use the oral bisphosphonates first, and if the patient cannot tolerate them because of reflux, we can move to the more potent agents.”
A large study of adjuvant denosumab has accrued, and the results should prove interesting, the specialists agreed. ■
Disclosure: Dr. Hurvitz has received research funding from Amgen, Bayer, Boehringer Ingelheim, Genentech, GlaxoSmithKline, Lilly, Novartis, Dignitana, Pfizer, Roche, BioMarin, Merrimack, OBI Pharma, Puma Biotechnology, and Medivation. Drs. Rimawi and Arteaga reported no potential conflicts of interest.
Addition of the oral bisphosphonate ibandronate to endocrine therapy did not significantly improve disease-free survival in patients with early breast cancer, according to the first results from the Dutch TEAM IIb trial presented at the 2016 San Antonio Breast Cancer Symposium.1