Tommy Nagle comes from generations of Pennsylvania farmers. He’s a cattle and row crop farmer himself. Many of his family members had melanoma, a type of skin cancer.
“My grandfather had it. My uncles have it. We're exposed to the sun a lot more than average people, because our jobs are mainly outside. It is something that is prevalent in farmers due to increased sun exposure 365, 14 hours a day,” Nagle said.
Nagle serves as vice president for the Pennsylvania Farm Bureau. He’s always looking for safety information to share with agricultural professionals. A recent study by Pennsylvania State University scientists shows that the high incidence of melanoma in his family of farmers is part of a pattern.
Their research found a 15-county melanoma "hotspot" in the central part of the state, including counties either with or near cultivated farmland.
The 15 counties are: Adams, Center, Columbia, Cumberland, Dauphin, Franklin, Juniata, Lycoming, Mifflin, Montour, Northumberland, Perry, Snyder, Union and York.
Central Pa.'s melanoma hotspot
The research, published in November in the journal JCO Clinical Cancer Informatics, analyzed five years of data from the state’s cancer registry from 2017-2021. The analysis found that adults 50 and older in the hotspot were 57% more likely to develop melanoma than residents living elsewhere.
The study only determined a pattern of melanoma, but not a cause in these communities.
“There was an association between this land cover as well as the agricultural chemical usage. That does not necessarily mean that it specifically comes from that. This is a correlation, not a causation study,” said Dr. Eugene Joseph Lengerich, an emeritus professor at Penn State’s College of Medicine and one of the study's authors.
Benjamin Marks, a student at Penn State College of Medicine and a co-author, said each county in the hotspot had to meet certain qualifications.
“The county itself, plus its six surrounding neighbors ... has to both be elevated and so that's why, if you look at the map, some counties that have high incidence, such as Wyoming or like Lancaster, are not included in the clusters, because the surrounding counties do not meet that neighborhood requirement,” Marks said.
But that does not mean the risk of melanoma is completely minimized in non-hotspot counties.
“There's this 15-county hotspot, and even counties touching that hotspot are also at an increased risk,” Marks said.
Nagle, for example, is from Cambria County, which is not one of the 15.
Dr. Charlene Lam, an associate professor of dermatology at Penn State and another co-author, noticed a high incidence of melanoma in her patients who were farmers.
“In no way is this study blaming our agricultural workers at all, but I think it's more of a demonstration of how we care and how this research can help us understand more about targeted prevention, as knowing that there might be high risk areas,” Lam said.
It was important to isolate melanoma in the study, according to Lengerich.
Cancer "is a lot of different diseases, and they each have their own characteristics, and therefore it really is appropriate to look for most cases, to be able to look at them individually, so that is part of the reason for only looking at melanoma,” he said.
A ‘one health’ approach
The study aligns with the scientists’ one health approach to healthcare.
“This study fits into the bigger picture that the growing popularity of a one health approach, which is really trying to integrate environmental, animal, human health, and so instead of looking at them in different silos, it's saying, we're all interconnected. It's these multifactorial processes that are affecting all living things. It's kind of looking at melanoma through that aspect which traditionally might have been overlooked,” Marks said.
This can help people living in the counties understand how to protect themselves against environmental factors.
“We are very much supportive of a one health approach to preventive medicine to human health as well, recognizing that human health is a composite of what goes on in our environment, and we really need to be able to look at it in that perspective,” Lengerich said.
Implications of the melanoma hotspot
The scientists hope farmers integrate prevention.
“An ounce of prevention is worth a pound of cure. If we can do things to educate and bring more knowledge to our community, that's a great way, because by the time they see me, it's already to the point where they're diagnosed with skin cancer. So, what can we do before that," Lam said.
A big takeaway from the study is that the melanoma risk in the hotspot counties is not isolated to people who live and work on farms.
“One of the first implications is that this is a preventable cancer,” Lengerich said. “A second implication is that our study does find that there is some risk that may be coming from the agricultural industry. That risk, though, is not specific to farms or farmers. It is for the entire population of that county.”
Marks does not want the research to worry people.
“The takeaway is not panic; it is that people in these counties, especially those who work in agriculture or outdoors, or who live in high-agricultural areas, should be more intentional about prevention, including sun protection and regular skin checks,” Marks said.
As a farmer and a member of the Pennsylvania Farm Bureau, Nagle is happy that there’s more awareness about the hazards of the job. He hopes this research makes more farmers adopt some of the changes he and his family have already made on his farm.
“The older farmers were unaware of the risk of what sun caused. Younger farmers, I can speak for myself. I can speak for my children. They're out helping on the farm. We sunblock every morning when we leave. Cab tractors have helped with that because we spent numerous hours in tractors," Nagle said.
Such developments are in contrast to generations past, he said, when farmers didn't wear sunblock and "didn't have much protection from the sun."
The team said further research is needed to determine causes by observing farming practices in person.
“One of the things that's already underway is site investigations with farms and farmers in central Pennsylvania," Lengerich said.
