Addressing social and economic disparities in triple-negative breast cancer immunotherapy: a U.S.-focused review

Triple-negative breast cancer (TNBC) is an aggressive subtype with limited targeted therapies. Immune checkpoint inhibitors (ICIs) offer improved outcomes, yet disparities in access, utilization, and clinical benefit persist across racial, socioeconomic, and geographic groups. We conducted a narrative review of literature from PubMed, MEDLINE, and Google Scholar (2000-2025) focusing on disparities in TNBC immunotherapy. Eligible studies included clinical trials, observational cohorts, and reviews addressing trial participation, biomarker testing, treatment initiation, adherence, and outcomes, with attention to race, ethnicity, insurance status, and geographic location. ICIs improve progression-free and overall survival in select TNBC populations, but trial enrollment often underrepresents Black, Hispanic, and rural patients, limiting generalizability. Disparities in PD-L1 and other biomarker testing, insurance coverage, proximity to specialized centers, and treatment navigation exacerbate inequities in initiation and adherence. Socioeconomic adversity, structural racism, and comorbid conditions may further modulate tumor immune responsiveness, compounding inequities. Importantly, when patients from marginalized backgrounds receive ICIs, outcomes are generally comparable to those of more privileged populations, underscoring the potential of equitable access. Addressing these gaps requires inclusive trial design, standardized biomarker testing, expanded insurance coverage, patient navigation, and community-engaged care models to advance equitable delivery of immunotherapy for all patients with TNBC.