Cancer data quality and harmonization in Europe: the experience of the BENCHISTA Project – international benchmarking of childhood cancer survival by stage

IntroductionVariation in stage at diagnosis of childhood cancers (CC) may explain differences in survival rates observed across geographical regions. The BENCHISTA project aims to understand these differences and to encourage the application of the Toronto Staging Guidelines (TG) by Population-Based Cancer Registries (PBCRs) to the most common solid paediatric cancers.MethodsPBCRs within and outside Europe were invited to participate and identify all cases of Neuroblastoma, Wilms Tumour, Medulloblastoma, Ewing Sarcoma, Rhabdomyosarcoma and Osteosarcoma diagnosed in a consecutive three-year period (2014-2017) and apply TG at diagnosis. Other non-stage prognostic factors, treatment, progression/recurrence, and cause of death information were collected as optional variables. A minimum of three-year follow-up was required. To standardise TG application by PBCRs, on-line workshops led by six tumour-specific clinical experts were held. To understand the role of data availability and quality, a survey focused on data collection/sharing processes and a quality assurance exercise were generated. To support data harmonization and query resolution a dedicated email and a question-and-answers bank were created.Results67 PBCRs from 28 countries participated and provided a maximally de-personalized, patient-level dataset. For 26 PBCRs, data format and ethical approval obtained by the two sponsoring institutions (UCL and INT) was sufficient for data sharing. 41 participating PBCRs required a Data Transfer Agreement (DTA) to comply with data protection regulations. Due to heterogeneity found in legal aspects, 18 months were spent on finalizing the DTA. The data collection survey was answered by 68 respondents from 63 PBCRs; 44% of them confirmed the ability to re-consult a clinician in cases where stage ascertainment was difficult/uncertain. Of the total participating PBCRs, 75% completed the staging quality assurance exercise, with a median correct answer proportion of 92% [range: 70% (rhabdomyosarcoma) to 100% (Wilms tumour)].ConclusionDifferences in interpretation and processes required to harmonize general data protection regulations across countries were encountered causing delays in data transfer. Despite challenges, the BENCHISTA Project has established a large collaboration between PBCRs and clinicians to collect detailed and standardised TG at a population-level enhancing the understanding of the reasons for variation in overall survival rates for CC, stimulate research and improve national/regional child health plans

Long-term survival and cure fraction estimates for childhood cancer in Europe (EUROCARE-6): results from a population-based study

Background: The EUROCARE-5 study revealed disparities in childhood cancer survival among European countries, giving rise to important initiatives across Europe to reduce the gap. Extending its representativeness through increased coverage of eastern European countries, the EUROCARE-6 study aimed to update survival progress across countries and years of diagnosis and provide new analytical perspectives on estimates of long-term survival and the cured fraction of patients with childhood cancer. Methods: In this population-based study, we analysed 135 847 children (aged 0–14 years) diagnosed during 2000–13 and followed up to the end of 2014, recruited from 80 population-based cancer registries in 31 European countries. We calculated age-adjusted 5-year survival differences by country and over time using period analysis, for all cancers combined and for major cancer types. We applied a variant of standard mixture cure models for survival data to estimate the cure fraction of patients by childhood cancer and to estimate projected 15-year survival. Findings: 5-year survival for all childhood cancer combined in Europe in 2010–14 was 81% (95% CI 81–82), showing an increase of three percentage points compared with 2004–06. Significant progress over time was observed for almost all cancers. Survival remained stable for osteosarcomas, Ewing sarcoma, Burkitt lymphoma, non-Hodgkin lymphomas, and rhabdomyoscarcomas. For all cancers combined, inequalities still persisted among European countries (with age-adjusted 5-year survival ranging from 71% [95% CI 60–79] to 87% [77–93]). The 15-year survival projection for all patients with childhood cancer diagnosed in 2010–13 was 78%. We estimated the yearly long-term mortality rate due to causes other than the diagnosed cancer to be around 2 per 1000 patients for all childhood cancer combined, but to approach zero for retinoblastoma. The cure fraction for patients with childhood cancer increased over time from 74% (95% CI 73–75) in 1998–2001 to 80% (79–81) in 2010–13. In the latter cohort, the cure fraction rate ranged from 99% (95% CI 74–100) for retinoblastoma to 60% (58–63) for CNS tumours and reached 90% (95% CI 87–93) for lymphoid leukaemia and 70% (67–73) for acute myeloid leukaemia. Interpretation: Childhood cancer survival is increasing over time in Europe but there are still some differences among countries. Regular monitoring of childhood cancer survival and estimation of the cure fraction through population-based registry data are crucial for evaluating advances in paediatric cancer care. Funding: European Commission