Suspected spatiotemporal cluster of childhood cancer in Lyon between 2013 and 2019. Investigation report.

In January 2020, the Center Léon Bérard (CLB) reported suspected excess cases of childhood cancer between 2013 and 2019 in children living in Lyon. The French public health service ARA launched a joint investigation with CLB based on the agency’s guidance. Two descriptive epidemiological studies were conducted: one based on data from the National Registry of Childhood Cancer (RNCE) and the other on computerized files of children treated at the Institute of Hematology and Pediatric Oncology (IHOPe/CLB) in Lyon. The main objective of these two studies was to determine the possible existence of an excess incidence of certain types of cancer in children in the 1st and 4th arrondissements of Lyon. These two descriptive epidemiological studies concluded that there is a statistically significant excess of cancer incidence (all cancers combined) in children aged 0 to 14 years living in the 1st and 4th arrondissements of Lyon compared with the rest Lyon and Caluir-i-i-de. Cuire (between 2010 and 2019 for the RNCE data study, 2015–2019 for the CLB data study). The standardized incidence ratio (SIR) for all sites was 1.66 (confidence interval [IC] at 95%: 1.05–2.49) for the French Public Health Study from the RNCE and 1.58 (95% CI: 1.10–2.10) from the CLB study. No excess incidence of a specific type of childhood cancer was found. During the period 2015–2019, Lyon also experienced a slight excess of childhood cancer incidence compared with France (SIR = 1.39; 95% CI: 1.20–1.59; CLB study). Analysis of existing environmental data in the study area failed to identify environmental impacts in the 1st and 4th arrondissements of Lyon that were different from those in the rest of the Lyon metropolitan region and likely related to childhood cancer. Air pollution levels are relatively high, but no higher than in the rest of the metropolitan area. Additionally, cancers associated with air pollution (specifically leukemia) do not occur in large numbers in the 1st and 4th arrondissements. Subsequently, a descriptive study was conducted among 10 families attending CLB for cancer screening. potential environmental impacts common to cases that would not have been identified until now. This study was carried out in the first quarter of 2022 in collaboration with oncologists and epidemiologists from CLB and IHOPe in Lyon. The study did not identify an exposure factor that was common to the identified cases, nor did it identify a place that more than four of the nine respondents regularly visited. Places visited by the three or four children included a school group, a municipal swimming pool and a public park. In each of these three sites visited, children had cancers of varying clinical sites. Overall, despite moderate excess incidence of cancer in children in all regions combined, no excess incidence of a specific cancer, diversity of anatomical and clinical forms of cancer in children occurring in expected age groups, no impact of proven or probable environmental risk factors, general for all or most of the cases present in the 1st and 4th arrondissements of Lyon, and not in the rest of the metropolis, are elements in favor of a probable random fluctuation of the pathology. These elements thus stand against the spatio-temporal cluster of childhood cancers characteristic of Lyon during the period 2010-2019, in the Croix-Rousse sector. The investigation was regularly monitored by a group of concerned parents and health professionals. A three-phase restitution (administration, guardians, parents) was conducted to present the results, collect suggestions and questions from stakeholders, and determine future directions. At the end of these restitutions, it was decided to carry out, three years after the publication of the report, an updated version of the study on the incidence of cancer in children in Lyon.

Author: Benet Thomas, Fervers Beatrice, Proud Delphine, Pepin Philippe, Ndokko Kate-Mary, Saura Christine
Year of publication: 2024
Pages: 63 p.
Collection: Research and surveys