Clinical and sociodemographic drivers of mortality in South Asian American women with breast cancer.

242 Background: Comprehensive data on breast cancer outcomes among South Asian American (SAA) women are limited, limiting efforts to optimize screening and treatment for this rapidly growing population. This study utilizes data from the National Cancer Database (NCDB) to evaluate differences in tumor characteristics, treatment patterns, and survival outcomes in SAA. Methods: Female SAAs (Asian Indian or Pakistani) diagnosed with invasive breast cancer between 2004 and 2021 were extracted from NCDB. Overall survival (OS) was modeled with multivariable Cox regression adjusting for age, stage, tumor grade, molecular subtype, Charlson–Deyo comorbidity index (CDI), insurance category, treatment delays > 60 days (surgery or chemotherapy), receipt of surgery, radiation, hormone therapy, and facility type. Results: The cohort comprised 20 561 South Asian American women. 5‐year overall survival was 93 % (95 % CI 92–94). In multivariable analysis, mortality increased with age: HR 1.22 (95 % CI 1.07–1.39) for ages 50–64, HR 1.60 (95 % CI 1.38–1.87) for ages 65–74, and HR 5.02 (95 % CI 4.31–5.84) for ages ≥ 75, versus 20–49. Compared with stage I, stage II had HR 1.97 (95 % CI 1.71–2.28), stage III HR 4.69 (95 % CI 4.03–5.47), and stage IV HR 19.96 (95 % CI 17.14–23.25). Grade 3 tumors carried HR 2.55 (95 % CI 2.07–3.15) versus grade 1, and triple-negative subtype HR 1.74 (95 % CI 1.30–2.32) vs. HR-/HER2+. Comorbidity burden increased mortality stepwise: CDI 1 HR 1.42 (95 % CI 1.23–1.64), CDI 2 HR 2.61 (95 % CI 1.94–3.51), CDI ≥ 3 HR 4.21 (95 % CI 2.85–6.21) versus CDI 0. Surgical delay > 60 days was associated with HR 1.59 (95 % CI 1.40–1.81). Protective factors included surgery (HR 0.11, 95 % CI 0.09–0.12), radiation (HR 0.61, 95 % CI 0.55–0.68), private insurance (HR 0.38, 95 % CI 0.32–0.46), and treatment at academic/research centers (HR 0.75, 95 % CI 0.60–0.94). Delay in chemotherapy > 60 days was not associated with increased mortality (HR 0.56, 95 % CI 0.48–0.64). Neighborhood income and public insurance status were not independently associated with survival. Conclusions: In SAA, OS was associated with tumor grade, molecular subtype, disease stage, comorbidity burden, and interval to surgery. Higher-grade and triple-negative tumors, advanced stage at presentation, greater comorbidity, and surgical delays longer than 60 days were each linked to higher mortality. In contrast, private insurance coverage and treatment at academic centers were associated with improved outcomes. These findings indicate that, in this population, earlier detection, phenotype-directed therapy, meticulous management of co-existing conditions, and prompt surgical intervention are particularly important for enhancing survival. Prospective studies combining genomic, immunologic, social, and treatment-timing data are needed to clarify biological drivers and to determine whether reducing care delays further improves outcomes.