Analysis of the Breast Cancer Journey in Namibia

Abstract

Importance: Breast cancer (BC) is the leading cancer among women in Namibia. Examining the BC journey in this multiracial country where inequalities remain large is needed to inform effective interventions to reduce BC mortality.

Objective: To describe the entire BC journey of Namibian women by race, utilizing the World Health Organization Global Breast Cancer Initiative (GBCI) framework.

Design, setting, and participants: This cohort study used the Namibian subset of the African Breast Cancer-Disparities in Outcomes prospective cohort. Participants were all Namibian residents with confirmed incident BC who presented at the main national public oncology center of the Windhoek Central Hospital (WCH). Follow-up started from recruitment (September 8, 2014, to October 5, 2016) and ended up to 3 years after diagnosis (December 13, 2014, to September 27, 2019). Data analysis was conducted from June 2022 to August 2023.

Exposures: Participants' self-reported ethnicities were aggregated into 3 population groups: Black, mixed ancestry, and White.

Main outcomes and measures: Three-year overall survival (OS) was examined using Cox models, and summary statistics were used to describe women's BC journey, including GBCI pillar key performance indicators: (1) early stage (TNM I or II) diagnosis (population benchmark ≥60%), (2) prompt diagnosis, ie, 60 days or less to first health care practitioner visit (population benchmark 100%), and (3) completion of recommended multimodal treatment (MT, ie, surgery plus chemotherapy) (population benchmark ≥80%).

Results: Of 405 women, there were 300 (74%) Black (mean [SD] age, 53 [15] years), 49 (12%) mixed ancestry (mean [SD] age, 53 [7] years), and 56 (14%) White (mean [SD] age, 59 [12] years) patients. Three-year OS was lowest in Black women (60% [95% CI, 54%-66%]; mixed ancestry: 80% [95% CI, 65%-89%]; White: 89% [95% CI, 77%-95%]), who had lower prevalence of early stage diagnosis (Black: 37% [95% CI, 31%-42%]; mixed ancestry and White: 75% [95% CI, 66%-83%]) and timely diagnosis (Black: 60% [95% CI, 54%-66%]; mixed ancestry and White: 77% [95% CI, 69%-85%]), while MT completion (Black: 53% [95% CI, 46%-59%]; mixed ancestry and White: 63% [95% CI, 50%-73%]) was low in all women.

Conclusions and relevance: In this cohort study of 405 Namibian residents with BC, marked racial disparities in survival were paralleled by inequities all along the BC journey. To improve BC survival, interventions are needed to promote earlier diagnosis in Black Namibian women and to increase MT initiation and completion in all women.

Figure.. Three-Year Overall Survival (OS) After Breast Cancer Diagnosis and Global Breast Cancer Initiative (GBCI) Key Performance Indicators (KPI) in the African Breast Cancer–Disparities in Outcomes (ABC-DO) Study, by Population Group and Macroregion

A, Three-year OS from breast cancer (BC) diagnosis. B, Maps displaying GBCI pillar 2 KPI, prompt BC diagnosis (benchmark ≤60 days). C, Maps displaying GBCI pillar 1 KPI (benchmark ≥60%). D, Maps displaying GBCI pillar 3 KPI, completion of recommended multimodal treatment (benchmark ≥80%). The maps in panel D represent the proportion of women with nonmetastatic breast cancer who completed surgery plus chemotherapy among those for whom these treatment modalities were indicated and who received surgery and/or chemotherapy. To avoid sparse data regions were aggregated into 5 macroregions as follows: Eastern, Omaheke and Otjozondjupa; Northern, Omusati, Oshana, Ohangwena, Oshikoto, Kavango West and Kavango East, and Zambezi; Western, Kunene and Erongo; Southern, Hardap and Karas; and Central, Khomas (where Windhoek, the country’s capital, is located) (eFigure 1 in Supplement 1). GBCI framework KPI estimates were calculated at the macroregion level. The relative contribution of each region to country total for each population group (Black and mixed ancestry and White Namibian women) is represented by case density (ie, proportion of women from a population group living in a specific region).