A Surprising Relationship: Parkinson’s Disease & Melanoma
Melanoma is a type of skin cancer that develops from melanocytes, and Parkinson’s disease (PD) is a progressive movement disorder that affects the nervous system… But did you know that these two conditions have something in common?
Research shows that people with PD have a higher risk of developing melanoma, and people with melanoma have a higher risk of developing PD. But what causes this relationship? How does family history increase your risk? And what should you do next?
The link between melanoma & Parkinson’s
The relationship between melanoma and PD runs both ways: Specifically, people with PD are 4x more likely to develop melanoma, and people with melanoma have 4x the risk of developing PD.1 Even given these statistics, it is important to know that many people with PD will not develop melanoma, and many people with melanoma will not develop PD. However, if you are affected by either of these conditions, you should talk to your doctor about your risk factors.
What about family history?
Melanoma and PD are both independently associated with family history: A person’s risk of melanoma increases if someone in their family has also experienced melanoma, and a person’s risk of PD increases (slightly) if they have a family history of PD. More surprisingly, a family history of one of these conditions may also impact your likelihood of being diagnosed with the other: Research shows that people with a family history of melanoma (in a first-degree relative) have twice the risk of developing PD.2 When possible, always keep your family medical history up-to-date, but if you have melanoma or PD, and have a family history of either of these conditions, be sure to talk to your healthcare providers.
Why is there a link?
Since the 1970s, researchers believed that levodopa (a common therapy for Parkinson’s disease) caused melanoma in people with Parkinson’s.1,3,4 Levodopa impacts the body’s creation of melanin and melanocytes, leading scientists to blame this drug for a higher incidence of melanoma in people with PD. Many research studies have since reported that levodopa does not cause melanoma, but no one knows exactly why this association between melanoma and PD exists.2,4
Although the exact relationship between PD and melanoma is still a mystery, researchers have suggested many other reasons for this association, including social-environmental factors, immune system irregularities, and genetics.
Both PD and melanoma are associated with melanin (the pigment that colors your hair, skin, and eyes)5. PD is caused by the death of dopamine-producing cells (which are high in melanin), while melanoma results from the overproduction of melanin-creating cells. Although these changes are different (PD results from the loss of cells, while melanoma results from the overproduction of cells), both conditions result from melanin-related abnormalities. Therefore, some researchers believe that people with PD and people with melanoma share the same immune system irregularities2.
Melanoma and PD are associated with some of the same non-changeable, genetic factors, such as race, sex, and skin type. Your risk of PD and your risk of melanoma both increase if you are a man, if you are White, and/or if you have fair skin.6,7 Therefore, based on these genetic similarities, some researchers believe that the same genetic abnormality affects both people with PD and people with melanoma.1,3
What should I do if I have Parkinson’s disease?
People with PD should have regular screenings for melanoma, which may include seeing a dermatologist for a total body skin exam.1,2,4 People affected by PD should also take steps to minimize their risk of melanoma, such as reducing UV exposure and checking your skin regularly for any changes. You should also talk to your PD providers about melanoma.
What should I do if I have a history of melanoma?
Unlike melanoma, PD is an idiopathic disease, meaning that it occurs spontaneously, without a known cause. Therefore, people with melanoma cannot take steps to prevent PD. However, if have a history of melanoma, you can work with your healthcare provider to look for early symptoms of Parkinson’s disease, as well as discuss your family history.
Do you live with any sleep disorders (eg. insomnia, RLS, sleep apnea) in addition to PD?