Bone health and antiresorptive agent use in Asian American Pacific Islander (AAPI) women with breast cancer.

e12696 Background: AAPI women with breast cancer (BC) may be at increased risk for poor bone health due to lower bone mineral density (BMD) and prolonged antiestrogen therapy with a younger age at diagnosis. However, data on bone health screening, antiestrogen therapy-related bone loss, and antiresorptive agent (ARA) use in this population are limited. We compared bone health screening with dual energy x-ray absorptiometry (DXA), BMD after diagnosis, annual loss in BMD, and ARA use between AAPI and White women with BC. Methods: We conducted a multicenter retrospective study of AAPI and 1:1 random age-matched White women diagnosed with BC from 2020-2024 at 1 academic and 4 community sites. Primary outcomes included DXA screening rates within 1 year of diagnosis, BMD on initial DXA, and ARA use. Secondary outcomes included annual loss in total hip BMD. Multivariable logistic and linear regression models were used for statistical analysis. Results: 246 AAPI and 275 White women were analyzed. Mean (SD) age at diagnosis was 58 (13); 331 (65%) were postmenopausal, and almost all had stage 0-3 disease. AAPI had more stage 0 disease, lower body mass index (BMI), and were nonsmokers compared to White women (p < 0.05). Baseline DXA screening rates were similar in AAPI and White women (158 (64%) vs 185 (67%) respectively; adjusted OR 1.24, 95%CI 0.77-1.99). Mean baseline BMD at the spine, femoral neck, and total hip were significantly lower in AAPI women, and they had higher prevalence of osteoporosis 44 (28%) vs 31 (17%). The adjusted difference in spine BMD remained significant after controlling for menopausal status and BMI. Total hip BMD increased in White but remained unchanged in AAPI women, even when adjusted for menopausal status, BMI, aromatase inhibitor, and ARA use (Table 1). ARA use was low overall (23%) and did not differ significantly by race. Conclusions: Despite similar DXA screening rates, AAPI showed lower baseline BMD and more bone loss compared with White women with BC. These findings, together with low ARA use, suggest that current bone health management may be insufficient to mitigate antiestrogen therapy-related bone loss, particularly in AAPI women. Enhanced risk stratification, earlier intervention, and culturally-informed survivorship approaches, including optimization of bone-protective therapies, are needed to improve long-term skeletal outcomes in this AAPI population. Mean BMD & bone loss for AAPI & white women with BC. AAPIMean (SD) WhiteMean (SD) P-value Adjusted Mean Difference (95% CI)* Baseline Lumbar Spine BMD (g/cm 2 ) 0.92 (0.16) 1.00 (0.19) <0.0001 0.04 (0.01, 0.07) Baseline Femur BMD (g/cm 2 ) 0.69 (0.12) 0.73 (0.13) 0.017 0.01 (-0.01, 0.03) Baseline Hip BMD (g/cm 2 ) 0.86 (0.16) 0.90 (0.15) 0.049 0.00 (-0.03, 0.04) Annual Loss in Total Hip BMD (g/cm 2 /year) 0.00 (0.06) -0.14 (0.18) <0.0001 -0.13 (-0.18, -0.08) *Adjusted for menopausal status, BMI, aromatase inhibitor, and ARA.