Pesticides and Other Common Chemicals Could Raise Breast Cancer Risk

Ronnie Cohen

August 02, 2021

(Reuters Health) — Nearly 300 chemicals found in everything from pesticides to food additives, cosmetics and even water could be increasing the risk of breast cancer in American women, a new study shows.

After combing through US Environmental Protection Agency testing data on more than 2,000 chemicals, scientists identified 296 that stimulated laboratory cells to produce estrogen or progesterone — hormones known to fuel breast tumors, they report in Environmental Health Perspectives.

"The connection between estrogen and progesterone and breast cancer is well established. So we should be extremely cautious about chemicals in products that increase levels of these hormones in the body," said co-author Ruthann A. Rudel, research director at Silent Spring Institute in Newton, Massachusetts.

The chemicals — which could be virtually anywhere in homes, furniture, food, water, shampoos, hair dyes and pesticides — were more likely to be carcinogenic or developmental or reproductive toxicants than not, Rudel told Reuters Health in a phone interview.

"I think industry can and should do more, and I really hope they'll scrutinize this list," she said. "There's an opportunity to reformulate based on this list right now."

Rudel and her co-author, Silent Spring scientist Bethsaida Cardona, urged regulators and manufacturers to view their research as a wake-up call to test chemicals for safety.

In addition, Rudel said she hopes breast cancer researchers will perform human and animal studies on the chemicals she identified. She also called for stricter regulation of chemicals that could promote the growth of breast cancer.

"Further effort in identifying breast carcinogens is urgently needed because female breast cancer has become the most commonly diagnosed cancer type in the world and the lead cause of cancer death in women globally," write Kathryn Guyton and Mary Schubauer-Berigan in an accompanying perspective. Guyton works for the National Academies of Sciences, Engineering, and Medicine, and Schubauer-Berigan works for the International Agency for Research on Cancer.

Of the chemicals that Rudel and Cardona identified as increasing estrogen and progesterone, 33 have been classified as either carcinogenic, probably or possibly carcinogenic. They found no information on breast carcinogenicity for 32 of the chemicals.

"It's kind of like, if you don't look, you're not going to find," said Linda Birnbaum, scientist emeritus and former director at the National Institute of Environmental Health and the National Toxicology Program. She was not involved with the new study.

"We need to look at more of these chemicals and relook at many of them," she said.

Many American consumers believe — mistakenly — that the government would not have allowed products to be sold in stores if they contain chemicals that might be harmful, but "that's not true," Rudel said. "There's a real gap."

"I would hope this paper does stimulate the EPA's Office of Pesticides and other regulatory bodies, including the FDA and the US Department of Agriculture, to look at these things more thoroughly," said Birnbaum, who is now a scholar in residence at Duke University in Durham, North Carolina.

But, she added: "These agencies are horrifically underfunded to do the job they've been given."

SOURCE: and Environmental Health Perspectives, online July 21, 2021.