Parkinson’s Disease Patients at Higher Risk for Melanoma

Study finds that people with Parkinson’s disease have a much higher risk of the skin cancer melanoma, and vice versa. Physicians treating patients with one disease should be vigilant for signs of the other in order to achieve early diagnosis and treatment, and patients should be educated about the risk of developing the other illness.

Medical experts have speculated about causes underlying the connection between Parkinson’s and melanoma for decades, with varying conclusions. Several studies have suggested levodopa, a drug for Parkinson’s, may be implicated in malignant melanoma, but others have found an association between the two diseases regardless of levodopa treatment.

According to a Mayo Clinic (Rochester, MN, USA) study led by Jose Pulido, MD: patients with Parkinson’s were roughly 4 times likelier to have had a history of melanoma than those without Parkinson’s, and patients with melanoma had a 4-fold higher risk of developing Parkinson’s. The study team used the Rochester Epidemiology Project medical records database to identify all neurologist-confirmed Parkinson’s cases from January 1976 through December 2013 among Olmsted County (MN, USA) residents. They examined the prevalence of melanoma in those 974 patients compared with 2,922 residents without Parkinson’s. They also identified 1,544 cases of melanoma over that period and determined the 35-year risk of Parkinson’s in those patients compared with the risk in people without melanoma.

The results support an association between Parkinson’s disease and melanoma, but argue against levodopa as the cause. It is likelier that common abnormalities underlie both conditions in patients who have both, but more research is needed to confirm that and refine screening recommendations.

“Future research should focus on identifying common genes, immune responses, and environmental exposures that may link these two diseases,” said first author Lauren Dalvin, MD, a Mayo Foundation scholar, “If we can pinpoint the cause of the association between Parkinson’s disease and melanoma, we will be better able to counsel patients and families about their risk of developing one disease in the setting of the other."

The study, by Dalvin LA et al, was published July 2017 in the journal Mayo Clinic Proceedings.

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