22 Pesticides Linked to Prostate Cancer

More research is needed to understand the potential environmental risk factors for this disease.

DenisProduction.com/Shutterstock

From food dyes in ultra-processed foods to microplastics, we’re constantly warned about chemicals in our environment that adversely affect health. While some are avoidable, some chemicals, such as pesticides, are essential for keeping food on supermarket shelves. However, a growing body of research suggests these crop-saving substances aren’t just killing pests.

A new study has identified 22 commonly used pesticides that are statistically associated with increased prostate cancer incidence across the United States. Still, researchers caution the observational design cannot establish direct causation.

The key message from this study is that there are likely environmental factors “such as exposure to certain pesticides” that contribute to prostate cancer risk, lead study author Simon John Christoph Soerensen of the Stanford University School of Medicine told The Epoch Times.

Pesticides a ‘Major Trigger’ for Cancer Development: NIH

​New research published on Nov. 4 in Cancer, a journal of the American Cancer Society (ACS), has further established a connection by identifying 22 pesticides consistently associated with increased prostate cancer rates.​

Story continues below advertisement

Four of these pesticides were “potentially clinically significant” because they were linked to death from prostate cancer.

Researchers analyzed county-level data on 295 pesticides and their link to prostate cancer rates across the United States. They accounted for a 10-to-18-year delay between pesticide exposure and prostate cancer onset, owing to the slow-growing nature of this cancer.

Among the 22 pesticides associated with increased prostate cancer incidence, three had previously been linked to prostate cancer, including 2,4-dichlorophenoxyacetic acid (2,4-D), which is widely used in the United States to control weeds such as dandelions, clover, and thistles.

Since 2014, the incidence rate of prostate cancer in the United States has risen by 3 percent annually, with advanced-stage prostate cancer increasing by approximately 5 percent each year, according to the ACS. Globally, prostate cancer is among the most prevalent cancers, according to the World Health Organization.

Story continues below advertisement

A review of 62 studies published in 2021 by the National Institutes of Health (NIH) indicates that occupational exposure to pesticides acts as a “major trigger” for several types of cancer, including multiple myeloma, bladder cancer, non-Hodgkin’s lymphoma, leukemia, breast cancer, and prostate cancer.

Exposure to 2,4-D and Other Identified Pesticides

People and their pets may be exposed to 2,4-D when they play or walk on treated grass. This pesticide is marketed under several brands, including Weed-B-Gone, Acme, and Aquakleen.

The remaining 19 pesticides identified in the study had not been previously associated with prostate cancer, encompassing a variety of herbicides, fungicides, insecticides, and a soil fumigant.

Among these, four pesticides were explicitly linked to both increased incidence and mortality of prostate cancer. These included the herbicides trifluralin, cloransulam-methyl, and diflufenzopyr, and one insecticide, thiamethoxam.

Only trifluralin is classified by the Environmental Protection Agency as a “possible human carcinogen.” The others are either “not likely to be carcinogenic” or have evidence supporting “non-carcinogenicity.”

Soerensen added that this study “serves as an important first step” in identifying possible environmental contributors to prostate cancer, given the significant role pesticides may play in prostate cancer incidence and mortality.

“We are optimistic that further studies, aided by advanced epidemiological methods, will build on these findings and contribute to more informed public health decisions,” Soerensen said.

Study Had Significant Limitations

The study was observational and based on statistical associations, meaning the researchers did not establish a causal relationship between pesticide exposure and prostate cancer.

Story continues below advertisement

“This research demonstrates the importance of studying environmental exposures, such as pesticide use, to potentially explain some of the geographic variation we observe in prostate cancer incidence and deaths across the United States,” Soerensen said in a statement.

The researchers acknowledged additional limitations, including their inability to definitively link higher pesticide exposure among those diagnosed with prostate cancer compared to those who did not develop the disease.

Soerensen said that although these findings alone “don’t warrant immediate changes to public policy,” they do provide insights that could guide future research on environmental exposures and cancer risk.

“This information is crucial to better understanding how pesticides might influence prostate cancer and to identifying potential preventative strategies,” he said.