This data, which integrates population-based cancer registries and healthcare covariates, reveals significant disparities in outcomes based on regional access to radiotherapy, mammography, and essential medicines.
How WHO Predicts Global Breast Cancer Survival Rates
The WHO utilized a Bayesian hierarchical model to estimate survival for all member states, filling data gaps in countries without robust population-based cancer registries (PBCRs). To ensure accuracy, the model combined observed data from the CONCORD-3 study—which analyzed over 6 million diagnoses—with supplementary data from SURVCAN-3 and NORDCAN.
For countries lacking registry data, the model used five specific covariates to predict survival:
- The percentage of diagnoses classified as nondistant (localized) disease.
- A breast cancer medicines index measuring accessibility and cost.
- Radiotherapy unit density per million people.
- Mammography unit density per million women aged 50–69.
- Female all-cause adult mortality rates from the 2024 Revision of World Population Prospects.
The Impact of Healthcare Access on Patient Outcomes
The study identifies a direct link between a country’s healthcare infrastructure and its survival rates. The WHO integrated data from the Global Health Observatory to track radiotherapy and mammography density. In many regions, the “hurdle model” used by researchers accounted for a high number of countries reporting zero radiotherapy units, which correlates with lower net survival.
Medicine accessibility also played a critical role. Countries with higher index scores generally showed stronger survival correlations.
Regional Disparities and the African Region Gap
The most stark contrast in survival data appears in the African region. This figure was heavily influenced by hospital-based estimates from the African Breast Cancer-Disparities in Outcomes (ABC-DO) study, which covered 2,228 women across five sub-Saharan countries between 2014 and 2017.
Validation and Country Consultation
To maintain transparency, the WHO submitted preliminary estimates to member states for review between October 17, 2025, and February 4, 2026. For six of these countries, the WHO used the observed submitted data as the final estimates without further modeling, noting a maximum difference of only 1.3% between observed and predicted values.
| Metric | Global Estimate | African Region Estimate |
|---|---|---|
| 5-Year Net Survival (Median) | 77.8% | 39.1% |
| 95% Uncertainty Interval | – 79.2% | – 44.7% |
Frequently Asked Questions
What is “net survival”?
Net survival measures the probability of surviving the cancer itself by removing the influence of other causes of death (background mortality) using life tables. This allows for a more accurate international comparison of how healthcare systems manage the disease.
Why are some survival estimates more reliable than others?
The CONCORD program considers estimates less reliable if 15% or more of patients have missing dates, were identified only via autopsy/death certificates, or were lost to follow-up within five years.
How does the model handle countries with no data?
The model uses “shrinkage,” where data-sparse countries borrow statistical strength from epidemiologically similar countries within the same Global Burden of Disease (GBD) super-region.
These findings underscore the critical need for expanded mammography screening and radiotherapy access to close the survival gap between high-income and low-income nations.
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