Problems with the Use of Aromatase Inhibitors in Breast Cancer

Abstract

The use of Aromatase Inhibitors (AI’s) in the adjuvant therapy of operable breast cancer is ubiquitous. All guidelines in widespread use advocate their use in hormone-receptor-positive breast cancer in post-menopausal women. Premenopausal hormone-receptor-positive women who are considered at high risk of relapse are also treated with drug- or surgically-induced ovarian suppression plus an AI following chemotherapy, producing somewhat better results than those seen with chemo followed by tamoxifen [1]. A major side effect of these drugs is the accelerated loss of bone mineral density (BMD). The use of bone-sparing agents such as bisphosphonates has become widespread but not routine in these patients. Whether or not they receive bone-sparing agents, patients on AI’s should receive periodic assessment of bone density. How do doctors comply with this common-sense approach? The answer: not as often as they should. The best data on this practice was published in the Journal of Oncology Practice in May 2017 from a group of investigators at Yale [2]. Using the SEER Medicare database they identified over 135,000 women diagnosed with breast cancer from 2007 to 2010. Using robust exclusion criteria for such things as metastasis at presentation, too brief exposure to bisphosphonates, in situ only cancer, and prior diagnosis of osteoporosis, they identified 2409 women who met all entry criteria and served as the population studied. Within this group only 51% received a DEXA scan at initiation of AI and only 34% had a second scan within three years of being on therapy. What the authors were not able to ascertain was how many of these patients were placed on a prophylactic bisphosphonate or equivalent at the start of AI therapy. What was clear is that age and race had a lot to do with who received a DEXA scan. 30% of women over 85 vs. 56% ages 67-69 were scanned. 53% of causasian women were scanned vs. 33% non-caucasian. Wonen with higher stage and more comorbidities were also less likely to have been scanned.