Conclusion of epidemiological investigations; continuation of active surveillance

In response to the requests made at the last Monitoring Committee meeting, Santé publique France conducted a study of the geographic distribution of pediatric cancers in Loire-Atlantique between 2005 and 2018, which involves comparing the situation in the Sainte-Pazanne area with the rest of the department. Due to the lack of comprehensive data, this work could not be carried out at the start of the investigation. The statistical analysis concludes that there is no abnormally high risk of pediatric cancers in the Sainte-Pazanne area compared to the rest of the department. To go further, a spatiotemporal scan analysis was conducted to identify, if they exist, clusters of pediatric cancers and whether these persist over time within the department. This analysis did not show the significant and persistent presence of clusters of childhood cancers in the department.

Furthermore, the investigation did not reveal any unusual exposure to a documented risk factor specific to this geographic area that could explain the cluster of cancers.

In an effort to adhere as closely as possible to the recommendations of the methodological guide for investigating clusters, and also in response to public concern, surveillance of pediatric cancers is being maintained in collaboration with the University Hospitals of Nantes and Angers and the registry.

Contributing to the advancement of knowledge in environmental health

Continuing and expanding research into the causes of pediatric cancers is essential to understanding how they arise, better preventing them, and improving the investigative tools available to address the public’s concerns regarding clusters of pediatric cancer cases.

For several years, Santé publique France has been committed to improving knowledge about pediatric cancers and, more broadly, about population exposures (metals, pesticides, etc.).

Regarding pesticides, Santé publique France has already launched, in collaboration with other partners, large-scale and unprecedented studies at the national level to assess the contribution of pesticides to the occurrence of pediatric cancers (Géocap-Agri) and to evaluate the level of exposure to these substances among the general population (Esteban study) or populations living near agricultural fields (Pestiriv study).

Reducing the population’s environmental exposure is also a priority objective. An information website, “Agir pour bébé”: https://agir-pour-bebe.fr/ was launched last September by Santé publique France to raise awareness among expectant parents and parents of newborns about the influence of environments (chemical, physical, social, emotional, etc.) during pregnancy and early childhood on their health and that of their child. The site offers a wealth of practical advice based on scientifically validated information.

Environmental investigations at the school, in homes, and at the former Leduc site

In addition to the epidemiological study, environmental investigations were conducted by the ARS and the DREAL—with support from several agencies and operators (IRSN, ADEME, SPF, HPC, etc.)—to identify any instances where reference values were exceeded and to take protective measures if necessary. Several campaigns were carried out starting in July 2019: Notre-Dame de Lourdes School, the housing development built on the former Leduc site, homes of children with cancer… Hundreds of samples and measurements were taken in water, air, soil, electromagnetic fields, and ionizing radiation…

For both the school and the housing development built on the former Leduc site, the results of the two measurement campaigns—conducted during the summer and winter—conclude that there is no health impact from the former timber treatment activities.

Areas of concern were identified in July 2019 at Notre-Dame de Lourdes School related to poor indoor air quality caused by the presence of pollutants: radon (from geological formations), formaldehyde (emitted by coatings and furniture), and lindane (linked to timber treatment).

A decrease in concentrations was observed during subsequent monitoring campaigns (November 2019, January, and June 2020). This positive trend is attributable to the ventilation protocols and the work carried out. The concentrations measured in the classrooms are below or very close to the reference value.

Regarding lindane, the concentrations found last June in dust on the floors of two classrooms located beneath the attic indicate the need for a new ventilation adjustment. At the request of the ARS, the OGEC and the DEC have postponed the return of children to these two classrooms, which was scheduled for the start of the school year. New samples are scheduled for early October.

Regarding electromagnetic fields, the measurements taken in the summer of 2019 (continuous measurements inside the school and in the courtyard) were repeated this time in mid-January, during a period of higher electricity consumption. These static measurements were supplemented by individual measurements (two teachers wore monitoring devices for 24 hours). In both cases, the measured values did not reveal exposure exceeding the guideline values, including those recommended for the location of facilities serving sensitive individuals. According to ANSES, these electromagnetic fields are typical in urban areas.

Fourteen homes of families with children diagnosed with cancer were investigated during the winter of 2019–2020. These investigations covered various environments (indoor air, soil, water) and parameters (chemical, bacteriological, and radiological). No situation warranted the implementation of immediate corrective measures. Summary reports, accompanied by recommendations where warranted, were sent to each family, and an “anonymized” collective debriefing was organized by the ARS on July 4.

These measurement campaigns, whether concerning the school or the homes, allow for action to be taken when the situation warrants it, to promote a health-friendly environment. However, these campaigns and their associated results do not call into question the conclusions of Santé publique France regarding the absence of an identified common cause capable of explaining the cluster of pediatric cancers observed.

Taking preventive action to improve living environments

To support and expand prevention efforts, the ARS and the Pornic Agglo Pays de Retz Urban Community have decided to undertake the development of a Local Health Contract (LHC). This initiative aims to mobilize all stakeholders and unite them around a shared project across the community’s territory. Improving indoor air quality, promoting an environment conducive to children’s health, combating substandard housing, reducing exposure to pesticides… The range of possible actions is broad, and some of them may, in agreement with the mayors concerned, be implemented as early as this year.

Furthermore, the Regional Health Agency (ARS), the Regional Directorate for Environment, Development, and Housing (DREAL), and the Regional Directorate for Agriculture, Food, and Forestry (DRAAF) have decided to fund a campaign to measure pesticide levels in outdoor air in the municipality of Sainte-Pazanne. This one-year campaign has just begun. These investigations, like the measurements taken over the past several years at five other monitoring sites in the region, aim to better identify pesticide exposure among the population.

Research continues at the national level on the origins and causes of pediatric cancers

Understanding the causes of pediatric cancers, identifying new therapeutic approaches for those with poor prognoses, minimizing long-term effects, and improving the quality of life for children and adults who have survived childhood cancer remain major priorities for the National Cancer Institute. To foster the emergence of new knowledge on these cancers, the Institute launched a call for projects in 2019 to structure data sharing among research teams and facilitate the mobility of young researchers. In 2020, it is issuing two new calls for projects aimed at supporting the research community, regardless of their research field or discipline.

The first is a call for applications to establish a consortium titled “Origins and Causes of Pediatric Cancers.” Its goal is to foster breakthrough innovations and promote the acquisition of new knowledge in the field of pediatric oncology.
The second is an open call for projects titled “High Risk – High Gain.” Its objective is to support highly innovative basic and translational research projects that open up original, unexplored avenues and produce concrete advances in pediatric oncology. It will fund original and bold research projects (conceptually new and risky) that lack sufficient preliminary data to be selected under traditional calls for projects.