Introduction: Aromatase inhibitors (AI) are the mainstay therapy for postmenopausal women with hormone receptor-positive early breast cancer (HR+ EBC). However, their use induces alterations in bone homeostasis, increasing the risk of osteoporosis and fractures, thus impairing quality of life. Elderly women commonly have decreased bone density at the time of EBC diagnosis and AI initiation. Also, this population is usually underrepresented in clinical trials, thus causing scarcity in available data to study the AI long-term effects on bone density among seniors. Hence, we aimed to assess in a real-world setting the clinical impact of bone health management (BHM) in elderly women undertaking AI. Methods: We conducted a 3-year retrospective cohort study of women with HR+ EBC under adjuvant therapy with AI. Patients were stratified according to age: 65-74 (A group) and ≥75 (B group) years old. Statistical analysis of collected data was performed using IBM SPSS v25.0. and StataIC v5.0. Results: A total of 282 patients was included. The median age was 74 years (65-98) and 48.6% of patients enrolled (n=137) were ≥75 years. The median time under AI was 50 months (1-108). AI-associated arthralgia was higher in the elderly group (46.7% vs. 34.5%; p=0.036) that also reported a significantly higher rate of treatment suspension due to AI intolerance (5% vs. 1%; p=0.025). Baseline bone densitometry (BBD) was carried out in a sample of 65.6% of patients and revealed osteopenia or osteoporosis in 82.2% of the sampled individuals. Despite that, only 68.8% and 16.6% of them started calcium/vitamin D supplementation and bisphosphonates therapy, respectively. The incidence of fracture was higher in the B group (17.5% vs. 8.3%; p=0.020), mostly in the radium (25%) and secondary to a fall. Increasing age (p=0.01) and history of previous fracture (p=0.07) independently predicted a fracture event in group B. Adjusting for intrinsic subtype and disease staging, patients with a fracture event had lower disease free-survival (DFS) (HR 4.25 95% CI 0.9-22, p=0.08), but these results were noted only in group A. Conclusions: Our study challenges some perceptions regarding the attention given to bone health in everyday practice. The clinicians' adherence to published guidelines on BHM was overall low, with BBD being performed in only two-thirds of patients. On the positive side, a few clinical suggestions spring from our results. The higher AI intolerance among elderly women opens the opportunity for alternative therapies, such as Selective Estrogen Receptor Degraders (SERD). Fall-preventive strategies should also be implemented especially in high-risk groups such as elderly women under AI. These practice recommendations are likely to foster quality of care and reduce private and public health costs.

Citation Format: Mafalda Miranda Baleiras, Leonor Vasconcelos de Matos, Leonor Fernandes, Maria Teresa Neves, Fátima Alves, André Ferreira, Helena Miranda, Ana Martins. Aromatase inhibitors and bone health in elderly women with early breast cancer: Real-world data [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-10-19.