PURPOSE The incidences of neuroblastoma (NB) differ significantly between various resource settings because of varying quality of cancer registries and underdiagnoses. This study aimed to evaluate current regional variations as reported by international cancer registries and the theoretical and reported differences in international NB incidences and to evaluate South Africa (SA) as a case for variable reporting. METHODS A comprehensive literature review on registries reporting on NB was performed to construct incidence tables. The SEER Program incidence of 10.5/million children was used to calculate the expected number of NB cases for each country. Registry data of NB cases between 2000 and 2016 were requested from The South African National Cancer registry (SA-NCR) and the South African Children's Tumour Registry (SACTR) for comparison and to perform a probabilistic linkage study. RESULTS Internationally, incidences varied between –97.1% and +80% compared with the SEER program. SA under-reported NB cases by an estimated 74.2%. Between 2000 and 2016, the SA-NCR reported between 23 and 51 cases/year, whereas the SACTR reported between 18 and 57 cases/year for the same period. The incidence reported by the SA-NCR varied between 1.5 and 2.8/million children under 15-year per year, whereas the SACTR reported 1.74-2.6 cases/million children. Both registries reported incidences less than high-income country. A probabilistic record linkage of the two registries resulted in a combined incidence of 2.9 cases/million children. CONCLUSION As with most low- and middle-income countries, SA has either a lower incidence or underdiagnoses of NB cases. The reasons for under-reporting are not clear, but can be due to undiagnosed NB cases with spontaneous regression, missed possible cases because of lack of autopsies, and diagnosed cases not recorded in registries.

Background/Purpose Stage at diagnosis is an important metric in treatment and prognosis of cancer, and also in planning and evaluation of cancer control. In sub-Saharan Africa (SSA), for the latter, the only data source is the population-based cancer registry (PBCR). For childhood cancers, the “Toronto Staging Guidelines” have been developed to facilitate abstraction of stage by cancer registry personnel. Although the feasibility of staging using this system has been shown, there is limited information on the accuracy of staging. Methods A panel of case records of 6 common childhood cancers was established. 51 cancer registrars from 20 SSA countries staged these records, using Tier 1 of the Toronto guidelines. The stage that they assigned was compared with that decided by two expert clinicians. Results The registrars assigned the correct stage for 53-83% of cases (71% overall), with the lowest values for acute lymphocytic leukaemia (ALL), retinoblastoma and non Hodgkin lymphoma (NHL), and the highest for osteosarcoma (81%) and Wilms tumour (83%). For ALL and NHL, many unstageable cases were mis-staged, probably due to confusion over the rules for dealing with missing data; for the cases with adequate information, accuracy was 72-73%. Some confusion was observed over the precise definition of three stage levels of retinoblastomas. Conclusions A single training in staging resulted in an accuracy, for solid tumours, that was not much inferior to what has been observed in high income settings. Nevertheless, some lessons were learned on how to improve both the guidelines, and the training course.

Background/purposeStage at diagnosis is an important metric in treatment and prognosis of cancer, and also in planning and evaluation of cancer control. In sub‐Saharan Africa (SSA), for the latter, the only data source is the population‐based cancer registry (PBCR). For childhood cancers, the 'Toronto Staging Guidelines' have been developed to facilitate abstraction of stage by cancer registry personnel. Although the feasibility of staging using this system has been shown, there is limited information on the accuracy of staging.MethodsA panel of case records of six common childhood cancers was established. A total of 51 cancer registrars from 20 SSA countries staged these records, using Tier 1 of the Toronto guidelines. The stage that they assigned was compared with that decided by two expert clinicians.ResultsThe registrars assigned the correct stage for 53%–83% of cases (71% overall), with the lowest values for acute lymphocytic leukaemia (ALL), retinoblastoma and non‐Hodgkin lymphoma (NHL), and the highest for osteosarcoma (81%) and Wilms tumour (83%). For ALL and NHL, many unstageable cases were mis‐staged, probably due to confusion over the rules for dealing with missing data; for the cases with adequate information, accuracy was 73%–75%. Some confusion was observed over the precise definition of three stage levels of retinoblastomas.ConclusionsA single training in staging resulted in an accuracy, for solid tumours, that was not much inferior to what has been observed in high‐income settings. Nevertheless, some lessons were learned on how to improve both the guidelines and the training course.