Baseline Clinical and Laboratory Profiles at Breast Cancer Diagnosis in Tanzania: Differences by HIV Status

ABSTRACT Background Women living with HIV (WLHIV) may present with distinct clinical and laboratory characteristics at the time of breast cancer diagnosis. While previous studies, including multi-country cohorts such as the ABC-DO study, have described baseline patient and tumor features, data on pre-treatment laboratory parameters in routine clinical settings remain limited. This study aimed to characterize baseline clinical and laboratory factors at diagnosis and assess differences by HIV status. Methods We analyzed data from women newly diagnosed with breast cancer at three tertiary hospitals in Tanzania. HIV status was obtained from medical records or provider-initiated testing. Baseline clinical and laboratory variables measured before systemic cancer therapy were evaluated. Multivariable logistic regression was used to identify factors independently associated with HIV status. Results Among 425 women with newly diagnosed breast cancer, 47 (11%) were living with HIV. Advanced disease at presentation was common across the cohort. Neutropenia (absolute neutrophil count <1.5 × 10⁹/L) was more frequent among WLHIV than among women without HIV (15% vs 3%) and remained independently associated with HIV status (adjusted odds ratio [aOR] 3.52, 95% confidence interval [CI] 1.26–9.79). Conclusions WLHIV more frequently presented with neutropenia and advanced disease at diagnosis. By demonstrating that clinically relevant differences in hematologic status are detectable at presentation using routinely collected data, this study addresses a key gap in real-world evidence from sub-Saharan Africa. These findings provide clinically actionable insight into baseline patient status at entry into cancer care and may inform early clinical assessment and supportive care planning in resource-constrained settings.