Background: Population-based cancer survival is a key measurement of cancer control performance linked to diagnosis and treatment, but benchmarking studies that include lower-income settings and that link results to health systems and human development are scarce. SURVCAN-3 is an international collaboration of population-based cancer registries that aims to benchmark timely and comparable cancer survival estimates in Africa, central and south America, and Asia.
Methods: In SURVCAN-3, population-based cancer registries from Africa, central and south America, and Asia were invited to contribute data. Quality control and data checks were carried out in collaboration with population-based cancer registries and, where applicable, active follow-up was performed at the registry. Patient-level data (sex, age at diagnosis, date of diagnosis, morphology and topography, stage, vital status, and date of death or last contact) were included, comprising patients diagnosed between Jan 1, 2008, and Dec 31, 2012, and followed up for at least 2 years (until Dec 31, 2014). Age-standardised net survival (survival where cancer was the only possible cause of death), with 95% CIs, at 1 year, 3 years, and 5 years after diagnosis were calculated using Pohar-Perme estimators for 15 major cancers. 1-year, 3-year, and 5-year net survival estimates were stratified by countries within continents (Africa, central and south America, and Asia), and countries according to the four-tier Human Development Index (HDI; low, medium, high, and very high).
Findings: 1 400 435 cancer cases from 68 population-based cancer registries in 32 countries were included. Net survival varied substantially between countries and world regions, with estimates steadily rising with increasing levels of the HDI. Across the included cancer types, countries within the lowest HDI category (eg, CÔte d'Ivoire) had a maximum 3-year net survival of 54·6% (95% CI 33·3-71·6; prostate cancer), whereas those within the highest HDI categories (eg, Israel) had a maximum survival of 96·8% (96·1-97·3; prostate cancer). Three distinct groups with varying outcomes by country and HDI dependant on cancer type were identified: cancers with low median 3-year net survival (<30%) and small differences by HDI category (eg, lung and stomach), cancers with intermediate median 3-year net survival (30-79%) and moderate difference by HDI (eg, cervix and colorectum), and cancers with high median 3-year net survival (≥80%) and large difference by HDI (eg, breast and prostate).
Interpretation: Disparities in cancer survival across countries were linked to a country's developmental position, and the availability and efficiency of health services. These data can inform policy makers on priorities in cancer control to reduce apparent inequality in cancer outcome.
Funding: Tata Memorial Hospital, the Martin-Luther-University Halle-Wittenberg, and the International Agency for Research on Cancer.
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