One of them, a case-control study, showed an elevated risk in individuals whose adipose tissue contained substances that are now banned.
“The association between pesticides and pancreatic cancer exists. It is of low magnitude but robust, concerning cumulative pesticides and three substances: Mancozeb, glyphosate, and sulfur in spray form,” said Mathias Brugel, MD, hospital practitioner at Basque Coast Hospital Center in Bayonne, France, during his presentation.
Regarding the four other liposoluble substances associated with an increased risk for pancreatic cancer in the second study, “their use has been banned since the 1990s, but they are still present in soils and in the air,” Dr. Brugel told this news organization.
For example, in Reims, France, the assessment of air quality by ATMO Grand Est revealed the presence of banned pesticides in the air, he added. However, Dr. Brugel stressed that a cause-effect relationship between pesticide exposure and the risk for pancreatic cancer cannot be established with these studies.
Incidence Rising Constantly
The incidence of pancreatic adenocarcinoma has been increasing steadily for more than 30 years. In France, nearly 16,000 new cases were reported in 2023, which represented an annual increase of about 2%. According to the National Cancer Institute, “pancreatic adenocarcinoma could become the second leading cause of cancer mortality by 2030.”
“This increase in incidence is particularly strong in France compared with other Western countries. The causes are still poorly understood. One might wonder whether environmental factors like pesticides are involved,” said Dr. Brugel.
Known to have a mechanism of action favoring oncogenesis, pesticides are suspected of being responsible for the rise in certain cancers, especially given their extensive use in France. In total, around 300 substances are authorized, and 65,000 tons are applied each year, making France the largest consumer of pesticides in Europe.
“Contamination is ubiquitous, meaning they are found in soil, water, air, and in individuals,” said Dr. Brugel. According to a study by the Institute for Scientific Expertise Research, pesticide residues were detected in 64% of hair samples taken from French volunteers.
The literature increasingly reported data suggesting a link between pesticide exposure and the development of certain diseases like cancer. A 2021 document by Inserm notably confirmed the strong presumption of a link between occupational pesticide exposure and pathologies such as non-Hodgkin’s lymphoma and prostate cancer.
High-Incidence Zones
To explore the link between pesticide exposure and pancreatic cancer, Dr. Brugel and his colleagues conducted the EcoPESTIPAC and PESTIPAC studies, the results of which were presented at this year’s conference.
In EcoPESTIPAC, researchers conducted a national ecological regression by dividing the entire French territory into 5529 spatial units. The number of pancreatic cancer cases per spatial unit per year (disease-mapping) was determined using the National Health Data System.
Nine chemicals, including glyphosate, were included, thus covering half of pesticide purchases in France. The cumulative quantity of pesticides, regardless of molecule, was also examined. Pesticide exposure was estimated by the median ratio between pesticide purchase and agricultural area per spatial unit over an 11-year period from early 2011 to the end of 2021.
Mor than 134,000 cases of pancreatic cancer were reported during this period. The analysis revealed three high-incidence zones located around Paris, in central France, and in the Mediterranean basin, while spatial units in the western region showed the lowest incidences.
The heterogeneous distribution of the disease suggests the involvement of risk factors, said Dr. Brugel. After adjusting for confounding factors such as smoking, the study showed an increased risk for pancreatic cancer associated with the cumulative quantity of pesticides and three specific substances: Sulfur in spray form, mancozeb, and glyphosate.