Iowa Cancer Study: 76% Figure Applies Only to Five Cancers, Not All

Key points

• The 76% figure cited by Gov. Kim Reynolds and officials refers only to excess cases in prostate, breast, lung, melanoma, and colorectal cancers, not all cancer types.
• When all cancer types are included, the study explains only about 35% of Iowa's excess cases, leaving roughly 1,304 unexplained cases per year.
• Lung cancer accounted for nearly half of the explained excess cases, with models including radon and smoking explaining all additional diagnoses in that category.
• Phase 1 of the $1 million study focused on behavioral and demographic factors, excluding agricultural exposures like pesticides, nitrate-contaminated water, and PFAS.
• Iowa has the second-highest cancer incidence rate in the U.S. and is one of only three states where rates are rising, with nearly 21,700 new diagnoses expected this year.

Background

Iowa has faced scrutiny over its high cancer rates, with nearly half of its counties exceeding rates in Louisiana's 'Cancer Alley.' In September 2026, the state launched a $15.9 million cancer prevention initiative, distributing radon kits and expanding telehealth, funded by a $209 million federal award. This followed a $1 million allocation in 2025 for a year-long cancer study by the University of Iowa and the Iowa Department of Health and Human Services, aimed at identifying drivers of the state's elevated cancer rates.

How outlets are covering it

The Des Moines Register emphasizes that the 76% figure is misleading when applied to all cancers, noting that only 35% of excess cases are explained when all types are included. It highlights the exclusion of environmental factors like pesticides and PFAS, which are central to Iowa's cancer debate. Iowa Public Radio and KCRG present the findings more positively, focusing on the potential for prevention through behavioral changes like quitting smoking and reducing alcohol consumption. KCRG notes that while behavioral factors explain much of the burden, environmental and genetic factors remain uninvestigated, with Phase 2 expected to be more difficult due to limited data availability. All sources agree that the study does not fully explain Iowa's high cancer rates, but differ in their emphasis on the implications for public health action.

Why it matters

The study's findings underscore the complexity of addressing cancer rates in Iowa. While behavioral factors explain a significant portion of excess cases in five major cancers, the exclusion of environmental factors leaves a substantial gap in understanding the state's overall cancer burden. This has implications for public health policy, as prevention efforts may need to address both modifiable behaviors and environmental exposures to effectively reduce cancer rates. The ongoing debate over the role of agriculture and chemical exposures in cancer risk remains unresolved, with Phase 2 of the study expected to take up to a year to complete.

What to watch

Phase 2 of the cancer study will focus on genetic and environmental factors, including pesticides, PFAS, and nitrate-contaminated water. This phase is expected to be more challenging due to limited data availability, with researchers noting that the state does not monitor air quality or pesticide usage comprehensively. The study's findings may inform future public health policies and funding allocations, with $93 million of the $209 million federal award already designated for cancer prevention, screening, and treatment services. Over the next five years, Iowa anticipates investing up to $240 million in cancer-related services, building on existing prevention efforts and the Iowa Cancer Plan.