Melanoma on the Rise: A Closer Look at Risks in Rural Pennsylvania

One Health

One Health is an approach that links the health of people, animals, and the environment. Rather than working independently, One Health encourages unified effort by people in the medical, veterinary, and environmental fields to maximize overall health.

This may seem to be an abstract idea, but farmers implement this principle every day.Modern facilities, such as dairy barns, have ventilation systems built into the structure. In the heat of summer, the high airflow is designed to improve air quality and reduce heat stress. But even in the cold weather, fans are used to provide fresh air and eliminate much of the humidity and odor created by the animals. While the design focuses on the animals in the barn, it also benefits the health of the people working there. Limiting dust particles, humidity, and ammonia also helps protect workers' airways. Farmers have been pioneers in implementing One Health.

Following this approach, Penn State Health and Penn State Extension began a collaboration in 2025. Physicians at Penn State Health had noticed an increase in melanoma, a type of skin cancer, in the central Pennsylvania farming community.Based on this clinical observation, researchers began a study of the incidence of melanoma across the entire state of Pennsylvania. Medical researchers, Benjamin Marks and Eugene Lengerich, joined Penn State Extension at a Perry County Dairy farm. The goal was to help medical professionals better understand the normal operations of a dairy farm. This visit allowed the investigators to learn about the daily routines on farms and the handling of chemicals. In addition, they gained a better understanding of the barriers that limit the adaptation of health safety practices.

In November of 2025, the researchers published an article showing an increase in melanoma in southcentral PA. (Marks et al., 2025). A map of data from the Pennsylvania Department of Health shows the incidence of melanoma in Central Pennsylvania based on the number of cases per 100,000 people. (Figure 1). The researchers performed extensive statistical analysis to ensure that this was not just a coincidence. The analysis compared the county in question with its six neighboring counties to determine whether the incidence was higher than that in the state as a whole. Multiple statistical methods confirmed that there truly is an increase in melanoma in a 15-county area in the southcentral region of Pennsylvania. (Figure 2).

The link between sunlight (ultraviolet light) exposure and melanoma has been well established. Based on this relationship, the researchers compared the ultraviolet (UV) levels across the counties. The differences, however, could not account for the increase in melanoma cases. This prompted an additional analyses into other possible environmental and occupational exposure.

Previous studies have shown an increased risk of melanoma among farm workers and a potential link to exposure to chemicals. (Fortes et al. 2016, Tucker et al. 2025) Using data from the National Land Cover Database and the USDA Census of Agriculture, Penn State Healthinvestigators compared land use across the state. They found an association between melanoma incidence and the amount of cultivated cropland (Figure 3). Roughly, every 10 percent increase in cultivated cropland above the Pennsylvania average equated to a 14 percent increase in the melanoma rates for adults over 50.

A similar pattern of herbicide use was observed in this area (Figure 4). The statistics were similar, with melanoma rates increasing roughly 13.5 percent for every 9 percent increase in herbicide-treated acreage. The association was not evident when comparing the overall farmland (including pasture and hay crops) across the state. (Figure 5)

It is important to understand that showing the association means that both are present in the same area. It does not prove that this is the cause of the increase in melanoma incidence. The data were evaluated on a county basis due to availability and to protect the privacy of everyone involved. The research did not examine the individuals' personal experiences and behaviors.

The researchers recognized that they needed a better understanding of actual field work and chemical usage, and how these may be related to melanoma prevention. Consequently, they sought out Penn State Extension to visit a typical central Pennsylvania farm. This study provides an excellent example of One Health. Farmers, veterinarians, and medical professionals should work together to protect the health of people, farms, and the environment.

The Bottom Line:

This research should heighten everyone’s awareness of the risk of melanoma in agricultural areas. Keep in mind that melanoma occurs across the state, so everyone should be aware. Steps to minimize the risk are:

1. Sun exposure is still a major risk factor for melanoma. The evaluation of sun exposure in this study was on a county basis. It did not account for the individual exposure within the counties. Agricultural jobs can increase UV exposure, particularly with the amount of time spent outdoors. The proper use of sunscreens, wide brimmed hats and sun blocking clothing can all help to minimize exposure.
2. Early detection of melanoma can save lives. Regular skin screenings by a dermatologist can help detect the first signs of melanoma.
3. Proper storage and handling of all chemicals, along with proper use of personal protective equipment, will help to minimize the risk.

This article used only a portion of the research from "Harvesting Risk..." (Marks et al. 2025) to raise awareness of melanoma in Pennsylvania and the potential link to agriculture. Awareness of these risks is important not only for the individual but also for the entire family's health.

References

1. Marks, Benjamin J., Jiangang Liao, Charlene Lam, Camille Moeckel, and Eugene J. Lengerich. 2025. "Harvesting Risk: An Ecologic Study of Agricultural Practices and Patterns and Melanoma Incidence in Pennsylvania." JCO Clinical Cancer Informatics (United States) 9 (Journal Article): e2500160. doi.org/10.1200/CCI-25-00160.
2. Fortes, Cristina PhD; Mastroeni, Simona MSc; Segatto, Marjorie M. MSc; Hohmann, Clarissa MSc; Miligi, Lucia MSc; Bakos, Lucio PhD; Bonamigo, Renan PhD. Occupational Exposure to Pesticides With Occupational Sun Exposure Increases the Risk for Cutaneous Melanoma. Journal of Occupational and Environmental Medicine 58(4):p 370-375, April 2016. | DOI: 10.1097/JOM.0000000000000665
3. Tucker, Sarah, Yi Du, Rishad Ahmed, Gleb Haynatzki, Suraj Adhikari, and Risto H. Rautiainen. "Dermal Exposure to Agrochemicals as Risk Factor for Skin Cancer in Farmers and Ranchers in the US Central States." American Journal of Industrial Medicine 68 (2025): 286–294. doi.org/10.1002/ajim.23696.