For the third year in a row, Iowa has the second-highest rate of new cancers in the country, according to the annual report from the Iowa Cancer Register (ICR) published in March. It’s also one of only three states where the rate of new cancers is rising, according to data from the National Cancer Institute.
In its 2026 Cancer in Iowa report, ICR estimates another 21,700 Iowans will be diagnosed with new, invasive cancers this year, and 6,400 Iowans will die from cancer. Both are increases from last year. The report also estimated that there are 175,290 survivors currently living in Iowa, an increase from previous years.
ICR found the new cancer rate “in young adults in Iowa is significantly higher than the U.S.” A data analysis published by the Washington Post last October found cancer rates among young adults in the Corn Belt “are rising more rapidly than in the country as a whole.”
“At the turn of the century, Iowa ranked 18th in the nation for cancer rates among adults under 50,” the Post reported. “Today, it’s fifth.”
The numbers describing Iowa’s cancer crisis can make it seem somewhat abstract — even the fact that more than one in every 20 Iowans has had a cancer diagnosis at one point in their lives, according to the ICR’s 2025 annual report. In the episode on cancer in his What’s Eating Iowa? video series, Art Cullen blends personal stories with summaries of scientific research on environmental risk factors for cancer. Those personal stories include Cullen’s.
Cullen, the Pulitzer Prize-winning editor of The Storm Lake Times Pilot and an icon of Iowa journalism, begins the January video with footage from the Mayo Clinic, where he was being treated for prostate cancer. Art isn’t the only member of his immediate family to be treated for cancer. All three of his brothers and his sister have, too.
“There are four Cullen boys and one Cullen girl, all siblings. The boys all had prostate cancer, and the girl a radical and rare form of breast cancer,” he told Little Village. “And there’s no genetic linkage. The oncologists believe it’s environmentally based.”
Cullen noted that his family is far from alone: “Northwest Iowa has the highest concentrations of prostate cancer and breast cancer in Iowa, which is a leading cancer state.”
“Why is Iowa uniquely plagued with cancer? Well, what is unique about Iowa?” he asked. “It’s the most cultivated place on Earth, first of all, and it’s laced with petrochemicals through that cultivation. Second, we’re the number one pork producer and we’re the number one egg producer. That’s a lot of manure, it’s a lot of shit floating around in the air.”
“Shit floating around in the air” isn’t just a rhetorical flourish. If you can smell the stench of manure produced by a confined animal feeding operation (CAFO), as many people in rural Iowa can, it’s worth thinking about what you might be inhaling with that aroma.
A study published last year on pollution from industrial-style pig farms in North Carolina found a protein found only in swine manure on household surfaces in homes within a mile of the farms.
In March, researchers from Yale published the results of a study examining 20 years of data from Iowa, California and Texas on cancer incidence and proximity to factory-farming operations. Residents in counties with the highest densities of factory farming — dairy operations in California, beef cattle CAFOs in Texas and hog CAFOs in Iowa — had higher rates of cancer incidence than people in other counties in their states.
“These facilities are known sources of environmental pollution, including air pollutants (e.g., ammonia, particulate matter, hydrogen sulfide) and water contaminants such as nitrates, which may have implications for human health,” Jiyoung Son, the study’s lead author, told the Yale Daily News in an email.
Iowa has the greatest number of CAFOs in the country. According to the most recent EPA data, there are 3,938 CAFOs in Iowa. The states in second and third place had 1,585 and 1,228. After that, it’s 522 and fewer.
Other studies have found elevated risks of a variety of cancers associated with pesticide exposure in the corn-growing states of the Midwest, and Iowa is one of the heaviest users of pesticides in the country. A study published in Frontiers in Cancer Control and Society two years ago found that adjusting for known cancer risks and other factors, pesticide exposure appeared to have an impact similar to smoking on the rate of cancer incidence.
Estimated agricultural use for the pesticides atrazine (left) and glyphosate (right) in pounds per square mile. Dark red areas indicate usage of over 63.35 lbs/mi2 and 114.64 lbs/mi2, respectively. — USGS, 2019
In addition to the other health problems linked to exposure to elevated nitrate content in drinking water — a chronic problem in Iowa, overwhelmingly caused by manure and fertilizer in farm runoff — a 2025 review of recent scientific literature found patterns of increased risk of several forms of cancer associated with exposure to nitrate levels even below the EPA standard of 10 mg per liter.
All of the statements above use qualified language like “associated with,” “linked to” and “may have implications” because cancer risk is a complicated topic. Any cancer can have multiple causes, attributable both to individual behavior and environmental factors. Some of the causes may involve exposure to a risk factor years ago.
Studying risk factors can also be complicated by corporations pushing back against research documenting the carcinogenic effects of their products. Older people will remember how tobacco companies spent decades denying smoking caused cancer and undermining confidence in medical research, delaying effective regulations.
Cullen sees the connection between likely environmental risk factors for cancer and Iowa’s dominant agricultural practices — row crops that heavily use fertilizer and pesticides, and CAFOs — as a main reason Iowa political leaders in a position to take action or even adequately fund research haven’t.
“The problem is we don’t really want to know,” he said. “Gov. Reynolds set aside a million dollars to research why Iowa is this hotspot for cancer, but a million dollars is a drop in the bucket.”
That million dollars is the funding for Drivers of Cancer in Iowa, a collaborative project by the University of Iowa College of Public Health and the Iowa Department of Health and Human Services. The project is focused on four topics: creating maps to show where the six most common types of cancer in Iowa — prostate, female breast, lung, melanoma, colorectal and HPV-associated cancers — occur in higher rates than expected; study prostate cancer screening to determine if differences in screening around the state effect rates of the cancer; review policies and programs in states similar to Iowa and evaluate what is working; and assess the data gathered by the project to improve cancer prevention. The ultimate goal is to understand what is contributing to Iowa’s high cancer rates.
Cancer rates in Iowa have been rising since 2013. Iowa has one of the fastest rising rates of melanoma in the country, as well as rising rates of prostate and breast cancer, which the project listed as key facts about cancer in Iowa when it launched. The state has the country’s highest rate of oropharyngeal cancer, a rare cancer linked to HPV, affecting the throat and mouth. Colorectal cancer rates are declining, “but remain higher than most other states.” The incidence of lung cancer is also declining “but more slowly than in other states.”
In February, the project published an interim report summarizing findings on demographic and behavioral factors related to cancer incidences. The project compared Iowa to five Midwestern states with similar demographic profiles and patterns of behavior (including smoking, binge drinking and diet): Minnesota, Nebraska, North Dakota, South Dakota and Wisconsin.
Based on 2022 data, researchers concluded “Iowa’s cancer rates are substantially higher than the U.S., but not generally much higher than the Midwestern cluster of states.” Still, compared to the other five states in the cluster, Iowa had the highest overall rate of cancer, as well as the highest rates of lung and colorectal cancer.
Within Iowa itself, researchers found that data from 2018-2022 showed 87 of the state’s 99 counties had “a significantly higher number of excess cases of overall cancer above what would be expected if each county had the same age-sex-specific rate as the U.S.”
In a presentation to the Iowa House on the interim report, Jacob Oleson, professor of biostatistics at the UI College of Public Health, explained that researchers began by looking at demographic and behavioral issues because that data was readily available from established state and federal sources.
“We wanted to start as soon as we can, and not spend time collecting data,” he told House members at the presentation in March. “We wanted to get whatever results we could as fast as we could. In order to do that, we had to use existing data.”
Oleson said, “as we move forward, we can start looking at more specific information, such as the environmental data that we’re working on collecting.”
Dr. Mary Charlton, professor of epidemiology at the UI College of Public Health and director of the Iowa Cancer Registry, explained some of the challenges of collecting data on environmental factors. For example, Iowa doesn’t track pesticide use.
“What we don’t know in Iowa is, what is the exposure to non-farmers or non-occupational people in terms of agriculture exposure?” Charlton told House members. “We don’t even know if and how they’re exposed to pesticides. … We talk a lot about water quality, and we should. We don’t talk a lot about air quality. What’s in the air relative to people who may live near farms. It may not increase their risk, but it might, and we don’t know.”
“In Iowa, we have really a skyscraper of risk factors,” Kerri Johannsen, the senior director of Policy and Programs at the Iowa Environmental Council (IEC), told Little Village. Johannsen is also one of the authors of Environmental Risk Factors and Iowa’s Cancer Crisis, a new report from IEC and the Harkin Institute for Public Policy & Citizen Engagement. The report is the result of an almost year-long review of the latest scientific studies and academic research on the relationship between environmental factors and cancer risk, and how they illuminate cancer trends in Iowa. Among the report’s 17 other co-authors and contributors are public health researchers, policy experts and one of the state’s leading oncologists.
“We recognize that individual choices or behavior — things like smoking, exercise, eating your vegetables — all of those things are really important in terms of keeping us in balance, keeping us healthy and keeping cancer at bay,” Johannsen said. But the cancer risks of personal choices have already received a lot of attention in the media, and in 2024, ICR used its annual Cancer in Iowa report to highlight binge drinking in Iowa and the risk of alcohol-related cancers.
“What is it that makes Iowa different? That’s what we really looked at, talking to people who have been studying this in Iowa for a really long time,” Johannsen said. “They pointed us in the direction of radon, pesticide and nitrate. And then PFAS, which is more of an emerging issue.”
PFAS are per- and polyfluoroalkyl substances, also known as “forever chemicals.” The category includes more than 12,000 different chemical compounds used extensively for most of the 20th century to make products water- and stain-resistant, as well as grease- and oil-resistant. They were also used in firefighting foams and some cosmetics. Surveys have found PFAS contamination in 94 percent of surface waterways in Iowa and in 30 percent of groundwater sources.
Environmental Risk Factors and Iowa’s Cancer Crisis explores what peer-reviewed scientific studies have revealed about the four risk factors, explaining the research in readily understandable language. Putting the information from those studies into an Iowa context, the report concludes:
- All of the most common cancers in Iowa (breast, prostate, lung, colorectal, and skin melanoma) have associations with environmental risk factors (pesticides, nitrate, PFAS, and radon).
- In Iowa, 13 of the 16 cancer sites identified in the report as connected to pesticides, nitrate, PFAS, and radon exceeded the U.S. incidence rate in the most recent five-year period (2017–2021).
- Of the adult cancers identified as associated with these environmental risk factors, 11 of the 15 cancer types are increasing in the total Iowa population.
- For people under 50 in Iowa, six of 10 cancer types associated with pesticides, nitrate, PFAS, and radon are increasing.
“It is very frustrating and dismaying that our policy-makers are not acting on even some of the most obvious low-hanging fruit when it comes to cancer prevention,” Johannsen said. She pointed to a bill that would change Iowa building code to require all newly constructed homes to have passive radon mitigation systems.
“It’s a common-sense, low-cost, very cost-effective thing to do for new construction,” Johannsen said.
Radon is a colorless, odorless and tasteless gas from the decay of radium, a naturally occurring radioactive metal found in relatively large quantities in Iowa’s soil. Radon quickly becomes inert, but some of the products created by its decay are carcinogens. It can seep into homes through the foundations, and is a leading cause of lung cancer in Iowa.
The bill requiring passive mitigation systems passed the Iowa House in March. The Senate placed the bill on its “unfinished business” calendar. Two days before the Senate adjourned for the final time this year, it passed the radon bill.
Both the Iowa House and Senate passed bills to provide $3 million for pediatric cancer research, but they will need to overcome a disagreement on where the money should come from before the end of this year’s session. But even the bills’ sponsors acknowledge how limited the funding is.
“Yes, it’s a tiny step forward,” Sen. Kara Warme, an Ames Republican and floor manager for the Senate bill, said during debate on the bill. “But for families who have a little one with cancer they are begging and pleading and praying for their little one to take a tiny step forward.”
Warme called the bill “the least we can do,” apparently unaware of any irony in those words.
There is a separate crisis within Iowa’s cancer crisis, one that is all too common in American public health. There are stark racial disparities in both cancer rate and cancer deaths in the state between Black and white Iowans.
“Iowa’s Black population has the highest rate of all new cancer cases” among all racial and ethnic groups in the state, a May 2024 report in ICR’s Cancer in Iowa Spotlight Series states. “The death rate for all cancers has decreased for all races/ethnicities over the last 20+ years, yet the rate among Iowa’s Black population remains higher compared to other racial/ethnic groups… [E]ven among White and Black populations of the same socioeconomic levels, there are disparities in health outcomes.”
“This leads researchers to look for other causes of these disparities, such as institutional and structural racism,” the report continues. “In Iowa, we need to better understand the causes/drivers of these disparities.”
Of course, research into institutional and structural racism is something the Trump administration isn’t interested in funding. And at the state level, institutional and structural racism is one of the “controversial topics” that Republican leaders in the legislature want banned from the classroom.
“It seems to me the fact that we don’t know [what’s driving cancer rates] says a helluva lot about Iowa,” Art Cullen says in his January video on cancer in Iowa.
Cullen was successfully treated for his cancer, as were his siblings.
“We’re all getting old and we all have ailments, but as far as the cancer goes, we appear to have everything under control,” he told Little Village.
At the Mayo Clinic, Cullen underwent cryoablation, a cutting-edge treatment that freezes and removes the tumor, while leaving the prostate intact.
“A whole new world opens up at the Mayo Clinic in Rochester, Minnesota,” he said. “Thank God for Medicare, because I never would have been able to access that care on just a typical health insurance policy.”
Cullen understood there would be a fundamental difference between the cancer care available at Mayo and what is available “from these really inadequate healthcare systems in rural Iowa,” but experiencing it firsthand was still eye-opening.
“Access to care is a whole different animal if you’re in Spencer, Iowa, or even Sioux City, compared to Rochester or Iowa City,” he said. “That’s one of the educations I’ve gotten from this. We’ve built a system in this state that’s imposing cancer on us and limits the ways we can get treated.”
This article was originally published in Little Village’s May 2026 issue.
