“People typically characterize cancer as a disease associated with aging,” said City of Hope OC President Annette Walker. “But cancer has a younger face.”
Many things come to mind when one thinks of Orange County—most of them positive. Typically, higher-than-average cancer rates are not among them. And yet, Orange County has the highest overall rate of cancer incidence in people under 50 across its neighboring southern California counties.
For some time now, City of Hope has been sounding the alarm on this very issue. Their researchers have pointed in particular to rising rates of colorectal, breast, thyroid, and melanoma cancers among younger adults. While cancer trends among older populations have received attention for decades, physicians are increasingly alarmed by how many diagnoses are now occurring in patients in their 30s, 40s, and 50s.
Across the entire state, Orange County produced some of the highest rates of lung and breast cancer in women under 50.
On paper, Orange County should theoretically perform better than many surrounding regions. Median incomes are relatively high. Smoking rates are comparatively low. Access to healthcare is strong in much of the county. Yet the available data suggests OC residents—especially ones younger than the median age of 66—are still developing cancer at unusually elevated rates.
“This is a concern to all of us at City of Hope, and it’s a concern to me as a member of this community and as a mother and a grandmother,” said City of Hope OC President Annette Walker. “It is counterintuitive to our goal of reducing cancer risk for each successive generation.”
Residents will naturally wonder if there’s any singular cause. All science seemingly suggests the answer involves layered environmental and behavioral pressures accumulating over decades.
In other words, there is no one easy answer.
“We cannot deny that a wide range of environmental factors—called ‘the exposome’—have rapidly changed in developed countries since the mid-20th century,” said City of Hope OC physician-in-chief Dr. Edward Kim. “There is evidence that some toxic exposures happen as early as in the womb or even in preconception germ cells. However, we have reason to believe changes to diet and lifestyle, especially in youth and early adulthood, could make a significant difference.”
That latter claim was affirmed by Dr. Misagh Karimi, a medical oncologist at City of Hope OC, who said that about half of all younger patients diagnosed with colon cancer are overweight.
Researchers at City of Hope also pointed broadly to “environmental carcinogens” as a source of “additional risk.” Increasingly, concerned residents have begun to question whether the county’s use of chemical herbicides in waterways like the San Juan Capistrano creek have a role to play.
Until recently, glyphosate-based herbicides were being sprayed along portions of San Juan Creek as part of vegetation management operations. The practice drew backlash after a coalition of local residents and environmental advocates known as the Creek Team (or Creek Team OC) began documenting and publicizing the spraying. It has since been paused, but only temporarily.
As Orange County itself grapples with the issue, the entire nation has an eye on Monsanto Company v. Durnell, a closely watched Supreme Court case which alleges the agrochemical company manufacturing Roundup failed to warn people the herbicide could cause cancer. A ruling is expected this summer. It could have sweeping implications across the nation.
Although it’s only one of the chemicals in use by the County, the debate around glyphosate is particularly fierce. Previously, the International Agency for Research on Cancer (IARC) classified glyphosate as “probably carcinogenic to humans” in 2015. Across around 1,000 studies, the IARC found “sufficient” evidence of cancer in experimental animals and “strong” evidence that glyphosate can induce DNA damage and oxidative stress.
Courts around the country have since produced multibillion-dollar verdicts against Monsanto in lawsuits brought by plaintiffs diagnosed with non-Hodgkin lymphoma after years of herbicide exposure.
The debate became more complicated as Roundup itself changed over time. Historically, glyphosate was the main active ingredient. But today, modern consumer “Roundup” products in the U.S. are now a mix of different formulations. Some still contain glyphosate, while others contain chemicals like triclopyr, diquat dibromide, fluazifop-P-butyl, and imazapic instead.
While glyphosate itself does not outright appear on the NTP “known” or “reasonably anticipated” carcinogen list published by the National Toxicology Program (NTP) of the U.S. Department of Health and Human Services, some contaminants or related compounds in commercial “Roundup” do. For example, 1,4-dioxane—which has been reported as a contaminant in some ethoxylated surfactants—is listed by the NTP as “reasonably anticipated to be a human carcinogen.”
None of this definitively proves glyphosate is responsible for Orange County’s younger residents developing cancer at unusually high rates. What is not contested is the reality that Orange County’s cancer rates are moving in the wrong direction for people who, statistically speaking, should still have decades of healthy life ahead of them.
“This is an age group that is often getting to their mid-career, they might have children and [are] taking their kids’ health more seriously than theirs,” Annette Walker told the OC Register in 2024. “People typically characterize cancer as a disease associated with aging. But cancer has a younger face.”
