MON-760 Prevention And Treatment Of Aromatase Inhibitors Induced Bone Loss In Postmenopausal Women With Breast Cancer: A Critical Appraisal Of Guidelines And A Suggested Algorithm

Abstract A. Bassatne: None. A. Boukhalil: None. M.T. Chakhtoura: None. G. El-Hajj Fuleihan: None. Background: Aromatase Inhibitors (AIs) are potent adjuvant therapy in postmenopausal women with non-metastatic breast cancer (NMBCa). AIs increase bone turnover and fracture risk. Methods: We conducted a systematic review to compare guidelines on bone health in postmenopausal women with NMBCa, and assess their strengths and quality. We searched 4 databases (2010-2019, update on-going). We screened titles, abstracts and full texts, abstracted data and assessed the quality of guidelines using the Appraisal of Guidelines for Research and Evaluation II (AGREE) tool, independently and in duplicate. We developed an algorithm based on our review to help guide clinical practice. Results: We identified 10 guidelines. All recommend FRAX calculation and risk factors assessment, including smoking, alcohol, vitamin D deficiency, inadequate calcium intake, history of fragility fractures, family history of osteoporosis, steroid use, and low body mass index. 5/10 guidelines recommended screening with bone mineral density (BMD) upon initiation of AI. All guidelines recommend smoking cessation, activity, moderate alcohol intake, optimizing vitamin D and calcium intake. All guidelines recommend starting bone active agents based on T-score cutoffs ≤-2.5 or <-2, with higher cutoffs (<-1.5 to <-1) in presence of risk factors in 3 guidelines. Other indications include FRAX-based thresholds, annual BMD decrease (4-10%) and history of fragility fractures. Treatment options include oral bisphosphonates (BP), intravenous BP and denosumab. Using AGREE, the majority of guidelines had low scores (<40%) for stakeholder involvement, rigor of development, applicability and editorial independence domains. Most guidelines had moderate scores (50-72%) in the scope and purpose domain and good scores (75-89%) in the clarity of presentation domain. In our algorithm, we suggest initiation of bone active agents when T-score ≤-1.5 or ≤-1 with a risk factor, trabecular bone score (TBS)-adjusted FRAX above the threshold, or presence of fractures (hip, vertebral or ≥2 peripheral). In high-risk patients, Denosumab 60mg or Zoledronic acid (ZA) 4mg every 6 months is suggested based on trial evidence. However, ZA 5mg yearly might be sufficient. Conclusion: Published guidelines for prevention and treatment of AI-induced bone loss vary in their recommendations and suffer limitations in the development process. Trial-based evidence for optimal frequency and dosing of anti-resorptive drugs is needed. Monday, June 3, 2024