Melanoma Clusters Identified in Pennsylvania Counties Near Farmland

WEDNESDAY, Nov. 19, 2025 (HealthDay News) — The incidence of melanoma clusters in South Central Pennsylvania, which has a substantial agricultural industry, is elevated, according to a study published online Nov. 14 in JCO Clinical Cancer Informatics.

Benjamin J. Marks, from the Penn State College of Medicine in Hershey, and colleagues examined the geospatial distribution of melanoma incidence in Pennsylvania, quantified its association with agriculture practices and patterns, and considered its relevance for cancer control in an ecologic design study. The analyses included county-level Pennsylvania data on the 2017 to 2021 incidence of invasive melanomas among adults aged 50 years and older.

The researchers found that in a 15-county cluster in South Central Pennsylvania, the incidence of melanoma was 57.1 percent greater; eight of the counties were designated as metropolitan. Cluster counties had significantly more cultivated land and herbicide-treated land than noncluster counties (mean, 19.8 versus 6.9 percent and 16.8 versus 6.5 percent, respectively). A 10 percent increase in cultivated land and a 9 percent increase in herbicide-treated acreage each independently corresponded to a 14 percent increase in incidence in adjusted models.

“The data suggest that areas with more cultivated land and herbicide use tend to have higher melanoma rates, but many other factors could be at play like genetics, behavior, or access to health care,” Marks said in a statement. “Understanding these patterns helps us protect not just farmers, but entire communities living near farmland.”

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