According to researchers at the Mayo Clinic, patients diagnosed with Parkinson’s disease could be at an increased risk of developing melanoma. Interestingly, the opposite association has also been identified, suggesting that people with melanoma should also be screened for Parkinson’s.
The link between the movement disorder and skin cancer is not newly-discovered, however the mechanism behind this relationship has yet to be confirmed. Some studies have implicated levodopa, a drug used to supplement the lack of dopamine in patients with Parkinson’s, in the development of malignant melanoma, however this medication does not explain all cases of the cancer.
“Future research should focus on identifying common genes, immune responses and environmental exposures that may link these two diseases,” said Dr. Lauren Dalvin, a Mayo Foundation Scholar in Ocular Oncology. “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.”
Using medical records from the Rochester Epidemiology Project, Dalvin and her colleagues identified all cases of Parkinson’s disease in Olmsted County, Minnesota between 1976 and 2013. In total, 974 Parkinson’s patients were diagnosed in that time. Using data collected from the 1,544 patients with melanoma diagnosed over the nearly 40-year study period, the researchers determined the risk of developing Parkinson’s, compared to the general population.
The study found that people with Parkinson’s were about four times more likely to develop melanoma, and vice versa. The researchers published their findings in the Mayo Clinic Proceedings.
According to their findings, the researchers do not believe that levodopa was the cause of melanoma in patients with Parkinson’s in this study. Dalvin and her colleagues concluded that the association is likely multifactorial, and a mix of genetic, environmental and immune system factors play a role.
They also stress that more research will need to conducted in order to confirm the link, given that the study only included patients living in a specific geographical area. Patients diagnosed with either Parkinson’s disease or melanoma should be made aware of the link and monitored for possible development of the associated condition.