More than 37,000 Minnesotans will receive cancer diagnoses in 2025, and around 10,000 will die from one of the many forms of the disease, according to the latest projections from the American Cancer Society.
Minnesota has one of the highest cancer rates in the country. There were 34,000 new diagnoses in 2021, the latest year for which complete data is available, adding up to the sixth-highest per-capita rate in the country.
Prior to 2015, Minnesota’s cancer rate was similar to the national average. But starting that year Minnesota’s rate started to climb while the country’s plateaued. More recently, Minnesota’s cancer rate has again been falling, but not as quickly as the rest of the country.
The reasons for that shift aren’t fully understood. Minnesota has especially high rates of blood cancers, like leukemia and lymphoma, as well as melanoma. It also has a strong health care system relative to other states, which may drive more effective cancer screening and detection. That robust health care also keeps Minnesota’s cancer mortality rates below the national average: people here are more likely to be diagnosed with cancer, but less likely to die from it.
Within Minnesota, there are also apparent geographic differences in cancer rates. Counties in parts of western Minnesota’s farm country have seen the biggest increases in new cancer diagnoses since the mid-2000s, and they also have the state’s highest rates of new diagnoses today.
Several counties in the Twin Cities metro, by contrast, have experienced decreasing rates of cancer diagnoses.
Teasing out the signal from the noise in data like this is a challenge. “Cancer” is a catch-all term encompassing hundreds of different diseases, each with a unique set of known and unknown risk factors. Environmental hazards, like chemical exposure or air pollution, are generally believed to play a much smaller role in cancer development than overall health and lifestyle factors like obesity, activity levels, diet and others.
“Although environmental carcinogens are responsible for some cancer cases, most cases appear to be related to lifestyle factors such as smoking,” the CDC notes. “Geographic variations in cancer rates are thought largely to reflect variations in these lifestyle factors.”
Rates of colorectal cancer diagnoses and death, for instance, are roughly 30% higher in northwest and southwest Minnesota than they are in the Twin Cities. And in the state’s rural areas, those cancers are less likely to be detected early in their development, when treatment is most effective.
“Statistically significant higher rates of late-stage colorectal cancer incidence in the Southwest and Northwest regions of the state than in the Metro region (42% and 44% higher respectively) suggest screening rates were low,” said Scott Smith, a spokesperson for the Minnesota Department of Health.
Some other types of cancer, including cancers of the kidney and lung, are more prevalent in Greater Minnesota. Still others, including liver and prostate cancer, are more common in the Twin Cities metro.
In recent years, researchers have increasingly found evidence of links between exposure to various agricultural chemicals and the development of some types of cancer. Fertilizer byproducts can make their way into drinking water, for instance, potentially increasing the risk of colon, kidney and stomach cancer.
Sewage sludge used as an agricultural fertilizer often contains so-called “forever chemicals” like PFAS, which may similarly contaminate groundwater and raise the risk of various cancers.
Many studies have also found links between common farm pesticides and some types of cancer. Those risks appear to be greatest for people who directly handle the chemicals over long periods of time.
“Data from the Agricultural Health Study has reported some associations with pesticides and specific cancers, but this study includes pesticide applicators rather than the general public,” said Jen Poynter, a professor of epidemiology who studies cancer at the University of Minnesota. “We still have a lot to learn about the role of agricultural chemicals and risk of cancer.”
Other studies have found that ambient environmental exposure to those chemicals, like living in a community surrounded by heavily agricultural areas, may also be a risk factor. A 2011 study conducted in California, for instance, found “evidence of an association between prostate cancer and ambient pesticide exposures in and around homes in intensely agricultural areas.”
A more recent study in the same state found that “exposure to certain pesticides through residential proximity to agricultural applications during pregnancy may increase the risk of childhood central nervous system tumors.”
A 2024 literature review concluded that “women in rural regions are at risk for exposure to pesticides by equipment decontamination, unprotected clothes washing, pesticide drift, chemical spraying in the field, and other routes of exposure in the household,” and that that exposure could augment the risk of breast cancer development. An earlier study from Western Australia found that women who said they had previously noticed pesticide spray drifting from nearby farmland were more likely to develop breast cancer.
There are many other studies like these ones. By and large, they can trace correlations between environmental exposures and cancer development, but definitively establishing causality is much harder.
“For a host of reasons, it is hard to draw conclusions from an ecological comparison that agricultural chemical exposure contributed to cancer rates,” Smith said. A lot of different chemicals are used in farm country, and “not all chemicals act the same on biological systems. Adding to the complexity is that not everyone who lives in an agricultural county is exposed to agricultural chemicals.”
He also noted that cancer rates in several ag-intensive western Minnesota counties are relatively low and decreasing, making it difficult to make any broad statements about whether and how much agriculture may be contributing to cancer risk in the state.
Poynter is leading a massive study of Minnesota families in the hopes of “understanding the association between exposures in the environment and risk of cancer,” she said. The study hopes to eventually enroll 10,000 families, and Poynter encourages anyone who wants to help understand the drivers of cancer in Minnesota to enroll.
Minnesota Reformer is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Minnesota Reformer maintains editorial independence. Contact Editor J. Patrick Coolican for questions: info@minnesotareformer.com.