Stage at diagnosis and survival by stage for the leading childhood cancers in three populations of sub-Saharan Africa

Abstract

The lack of accurate population-based information on childhood cancer stage and survival in low-income countries is a barrier to improving childhood cancer outcomes. In this study, data from three population-based registries in sub-Saharan Africa (Abidjan, Harare and Kampala) were examined for children aged under 15. We assessed the feasibility of assigning stage at diagnosis according to Tier 1 of the Toronto Childhood Cancer Stage Guidelines for patients with non-Hodgkin lymphoma (including Burkitt lymphoma), retinoblastoma and Wilms tumour. Patients were actively followed-up, allowing calculation of three-year relative survival by cancer type and registry. Stage-specific observed survival was estimated. The cohort comprised 381 children, of whom half (n = 192, 50%) died from any cause within three years of diagnosis. Three-year relative survival varied by malignancy and location and ranged from 17% (95% Confidence Interval [CI] 6-33%) for Burkitt lymphoma in Harare to 57% (95% CI 31-76%) for retinoblastoma in Kampala. Stage was assigned for 83% of patients (n = 317 of 381), with over half having metastatic or advanced disease at diagnosis (n = 166, 52%). Stage was a strong predictor of survival for each malignancy; for example, three-year observed survival was 88% (95% CI 68%-96%) and 13% (4%-29%) for localised and advanced Burkitt lymphoma, respectively (P < 0.001). These are the first data on stage distribution and stage-specific survival for childhood cancers in Africa. They demonstrate the feasibility of the Toronto Stage Guidelines in a low-resource setting and highlight the value of population-based cancer registries in aiding our understanding of the poor outcomes experienced by this population.