Herbert Cubasch

BACKGROUND: Breast cancer is the second leading cause of death from cancer in women in sub-Saharan Africa, yet there are few well characterised large-scale survival studies with complete follow-up data. We aimed to provide robust survival estimates in women in this setting and apportion the survival gaps. METHODS: The African Breast Cancer-Disparities in Outcomes (ABC-DO) prospective cohort study was done at eight hospitals across five sub-Saharan African countries (Namibia, Nigeria, South Africa, Uganda, and Zambia). We prospectively recruited women (aged ≥18 years) who attended these hospitals with suspected breast cancer. Women were actively followed up by use of a telephone call once every 3 months, and a mobile health application was used to keep a dynamic record of follow-up calls due. We collected detailed sociodemographic, clinical, and treatment data. The primary outcome was 3-year overall survival, analysed by use of flexible proportional mortality models, and we predicted survival under scenarios of modified distributions of risk factors. FINDINGS: Between Sept 8, 2014, and Dec 31, 2017, 2313 women were recruited from these eight hospitals, of whom 85 did not have breast cancer. Of the remaining 2228 women with breast cancer, 58 women with previous treatment or recurrence, and 14 women from small racial groups (white and Asian women in South Africa), were excluded. Of the 2156 women analysed, 1840 (85%) were histologically confirmed, 129 (6%) were cytologically confirmed, and 187 (9%) were clinically confirmed to have breast cancer. 2156 (97%) women were followed up for up to 3 years or up to Jan 1, 2019, whichever was earlier. Up to this date, 879 (41%) of these women had died, 1118 (52%) were alive, and 159 (7%) were censored early. 3-year overall survival was 50% (95% CI 48-53), but we observed variations in 3-year survival between different races in Namibia (from 90% in white women to 56% in Black women) and in South Africa (from 76% in mixed-race women to 59% in Black women), and between different countries (44-47% in Uganda and Zambia vs 36% in Nigeria). 215 (10%) of all women had died within 6 months of diagnosis, but 3-year overall survival remained low in women who survived to this timepoint (58%). Among survival determinants, improvements in early diagnosis and treatment were predicted to contribute to the largest increases in survival, with a combined absolute increase in survival of up to 22% in Nigeria, Zambia, and Uganda, when compared with the contributions of other factors (such as HIV or aggressive subtypes). INTERPRETATION: Large variations in breast cancer survival in sub-Saharan African countries indicate that improvements are possible. At least a third of the projected 416 000 breast cancer deaths that will occur in this region in the next decade could be prevented through achievable downstaging and improvements in treatment. Improving survival in socially disadvantaged women warrants special attention. FUNDING: Susan G Komen and the International Agency for Research on Cancer.

Advanced stage at diagnosis contributes to low breast cancer survival rates in sub-Saharan Africa. Living far from health services is known to delay presentation, but the effect of residential distance to hospital, the radius at which this effect sets in and the women most affected have not been quantified. In a periurban South African setting, we examined the effect of a geographic information system (GIS)-measured straight-line distance, from a patient's residence to diagnostic hospital, on stage at diagnosis in 1,071 public-sector breast cancer patients diagnosed during 2006-2012. Generalized linear models were used to estimate risk ratios for late stage (stage III/IV vs. stage I/II) associated with distance, adjusting for year of diagnosis, age, race and socioeconomic indicators. Mean age of patients was 55 years, 90% were black African and diagnoses were at stages I (5%), II (41%), III (46%) and IV (8%). Sixty-two percent of patients with distances >20 km (n = 338) had a late stage at diagnosis compared to 50% with distances <20 km (n = 713, p = 0.02). Risk of late stage at diagnosis was 1.25-fold higher (95% CI: 1.09, 1.42) per 30 km. Effects were pronounced in an underrepresented group of patients over age 70. This positive stage-distance association held to 40 km, and plateaued or slightly reversed in patients (9%) living beyond this distance. Studies of woman and the societal and healthcare-level influences on these delays and on the late stage at diagnosis distribution are needed to inform interventions to improve diagnostic stage and breast cancer survival in this and similar settings.

INTRODUCTION: Estimates of the proportion of estrogen receptor negative (ERN) and triple-negative (TRN) breast cancer from sub-Saharan Africa are variable and include high values. Large studies of receptor status conducted on non-archival tissue are lacking from this region. METHODS: We identified 1218 consecutive women (91% black) diagnosed with invasive breast cancer from 2006–2012 at a public hospital in Soweto, South Africa. Immunohistochemistry based ER, progesterone receptor (PR) and human epidermal factor 2 (HER2) receptors were assessed at diagnosis on pre-treatment biopsy specimens. Mutually adjusted associations of receptor status with stage, age, and race were examined using risk ratios (RRs). ER status was compared with age-stratified US Surveillance Epidemiology and End Results program (SEER) data. RESULTS: 35% (95% confidence interval (CI): 32-38) of tumors were ERN, 47% (45-52) PRN, 26% (23-29) HER2P and 21% (18-23) TRN. Later stage tumors were more likely to be ERN and PRN (RRs 1.9 (1.1-2.9) and 2.0 (1.3-3.1) for stage III vs. I) but were not strongly associated with HER2 status. Age was not strongly associated with ER or PR status, but older women were less likely to have HER2P tumors (RR, 0.95 (0.92-0.99) per 5 years). During the study, stage III + IV tumors decreased from 66% to 46%. In black women the percentage of ERN (37% (34-40)) and PRN tumors (48% (45-52)) was higher than in non-black patients (22% (14-31) and 34% (25-44), respectively, P = 0.004 and P = 0.02), which remained after age and stage adjustment. Age-specific ERN proportions in black South African women were similar to those of US black women, especially for women diagnosed over age 50. CONCLUSION: Although a greater proportion of black than non-black South African women had ER-negative or TRN breast cancer, in all racial groups in this study breast cancer was predominantly ER-positive and was being diagnosed at earlier stages over time. These observations provide initial indications that late-stage aggressive breast cancers may not be an inherent feature of the breast cancer burden across Africa.

PURPOSE: Reported breast cancer incidence is rising in South Africa, where some women are diagnosed late and have poor outcomes. We studied patient and provider factors associated with clinical stage at diagnosis among women diagnosed at the Chris Hani Baragwanath Academic Hospital in Soweto, Johannesburg in 2015-2016. METHODS: From face-to-face interviewer-administered questionnaires we compared self-reported socioeconomics, demographics, comorbidities, risk factors, personal and health system barriers, and from patient clinical records, clinical staging, receptor subtype, and tumor grade among 499 consecutive women newly diagnosed with advanced stage (III/IV) breast cancer versus those diagnosed early (stage 0/I/II). Logistic regression models were used to identify factors associated with advanced stage at diagnosis. RESULTS: Among the women, 243 (49%) were diagnosed at early and 256 (51%) at advanced stages. In the multiple logistic regression adjusted model, completion of high school or beyond (odds ratio (OR) 0.59, and greater breast cancer knowledge and awareness (OR 0.86) were associated with lower stage of breast cancer at presentation. Advanced stage was associated with Luminal B (OR 2.25) and triple-negative subtypes (OR 3.17) compared to luminal A, with delays >3 months from first breast symptoms to accessing the health system (OR 2.79) and with having more than 1 visit within the referral health system (OR 3.19) for 2 visits; OR 2.73 for ≥3 visits). CONCLUSIONS: Limited patient education, breast cancer knowledge and awareness, and health system inefficiencies were associated with advanced stage at diagnosis. Sustained community and healthcare worker education may down-stage disease and improve cancer outcomes.

Breast cancer (BC) survival rates in sub-Saharan Africa (SSA) are low in part due to advanced stage at diagnosis. As one component of a study of the entire journey of SSA women with BC, we aimed to identify shared and setting-specific drivers of advanced stage BC. Women newly diagnosed in the multicountry African Breast Cancer-Disparities in Outcomes (ABC-DO) study completed a baseline interview and their stage information was extracted from medical records. Ordinal logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for advanced stage (I, II, III, IV) in relation to individual woman-level, referral and biological factors. A total of 1795 women were included from Nigeria, Uganda, Zambia, and the multiracial populations of Namibia and South Africa, 1091 of whom (61%) were stage III/IV. Stage was lower in women with greater BC knowledge (OR 0.77 (95% CI: 0.70, 0.85) per point on a 6 point scale). More advanced stage was associated with being black (4.00 (2.79, 5.74)), having attended <secondary education (1.75 (1.42, 2.16)), having never heard of BC (1.64 (1.31, 2.06)), an unskilled job (1.77 (1.43, 2.20)) and pregnancy in the past 3 years (30% of ≤45 year olds) (1.63 (1.15, 2.31)), and were mediated through delays to diagnosis: symptom duration of ≥ 1 year (OR 2.47 (1.93, 3.15)). These findings provide further evidence that late-stage BC in SSA is largely attributed to modifiable factors and strategies to improve BC education and awareness in women and the health system should be intensified.