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IARC 60th Anniversary - 19-21 May 2026

Session : 19/05/26 - Posters

Breast cancer overall survival, annual risks of death, and survival gap apportionment in sub-Saharan Africa (ABC-DO)

MO T. 1, JOFFE M. 2, GALUKANDE M. 3, PARHAM G. 4, ZIETSMAN A. 5, OFFIAH S. 7, CUBASCH H. 8, ANGELICA A. 9, PINDER L. 4, DOS-SANTOS-SILVA I. 6, MCCORMACK V. 1

1 The International Agency for Research on Cancer, Lyon, France; 2 University of Witwatersrand, Witwatersrand, South Africa; 3 Makerere University, Kampala, Uganda; 4 UNC Zambia, Lusaka, Zambia; 5 Windhoek Central Hospital, Windhoek, Namibia; 6 London School of Hygiene and Tropical Medicine, London, United Kingdom; 7 Abia State University Teaching Hospital, Aba, Nigeria; 8 University of the Witwatersrand and Chris Hani Baragwanath Academic Hospital, Johannesburg, South Africa; 9 Federal Medical Centre, Owerri, Nigeria

Background: Breast cancer (BC) is leading cancer and cause of cancer mortality amongst women worldwide, including being the second leading cause of death from cancer in women in sub-Saharan Africa (SSA). However, there are few estimates of breast cancer survival and its determinants at 5 years and beyond in SSA.
Objectives: We aimed to estimate survival up to 7 years, provide annual estimates of 1-year conditional survival, and assess how deaths can be averted by predicting survival gains if the distributions of prognostic factors were shifted in alignment with WHO’s Global Breast Cancer Initiative (GBCI).
Methods: The prospective African Breast Cancer-Disparities in Outcomes (ABC-DO) cohort study recruited women ≥18 years with newly diagnosed breast cancer at 8 major hospitals in Namibia, South Africa, Uganda, Zambia, and Nigeria. Vital status was updated via phone calls every 3 months for 7 years. We estimated age-standardized net survival (ASNS), conditional survival, and predicted survival gaps under scenarios of modified distributions of risk factors.
Results: Between September 8, 2014, and December 31, 2017, 2313 women were recruited and followed to January 1, 2022, and for a further year in South Africa. A total of 2153 women were eligible, among which 1323 (61%) died, 672 (31%) remained alive, and 158 (7%) were lost to follow-up, giving crude survival at 3, 5 and 7 years of 51%, 40% and 33% respectively. Large between-country variations in 5-year ASNS were observed: 35–42% in Zambia and Nigeria, 52–58% in Black women in Uganda, South Africa and Namibia, and over 83% in non-Black Namibian women. The annual probability of death (1-year conditional net survival, censored prior to Covid) declined generally from 2 to 3 years post-diagnosis, but remained at 8–21% for Black women in Namibia, Uganda and Nigeria during the fifth year post-diagnosis. Reaching the GBCI 60% stage I/II target, and accessing treatment would lead to an approximate one third reduction in deaths amongst Black women.
Conclusions: Survival after breast cancer is low in several SSA countries, with substantial risk of dying even amongst women who have survived over 3 years. Endorsing WHO’s GBCI, a large proportion of these deaths can be averted by strengthening early diagnosis and clinical care, greatly contributing to reducing avoidable deaths of women in these settings. 

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Overall survival up to 7 years since breast cancer diagnosis, by country-race ( the ABC-DO cohort)