This study explores the efficacy of desonumab in mitigating aromatase inhibitor-induced bone loss (AIBL) and osteosarcopenia in elderly women with breast cancer. The study involved 60 patients (female sex > or equal 65) with non-metastatic breast cancr and undegoing adiuvant endocreine therapy (Letrozole and Tamoxifen). Patients were divided as follows: 30 patients undergoing denosumab therapy (60 mg via subcutaneous injection every 6 months) and 30 patients undergoing bisphosphonate therapy (oral alendronate 70 mg/week). For each patient of the desonumab group bone status and muscoloskeletal composition was assessed by bone densitometry together with comprehensive geriatric assessment (CGA) and body composition at baseline and after one year of treatment. A significant improvement for trabecular bone score (TBS) at hte lumbar spine, relative skeletal muscle index (RSMI) and whole-body composition (arm, legs and trunk) were observed in the desonumab group compared with the bisphopshonate group. These findings underscore the role of desonumab as an effective strategy in managing AIBL and osteosarcopenia in elderly women with breast cancer and undergoing adjuvant endocrine therapy, which is crucial for improving quality of life, preventing functional decline, and optimizing treatment outcomes