Parkinsons and Melanomas

Why do I have a  photo of my late father in this blog?  I have a photo of my handsome, Irish father mostly because Father’s Day is coming up.   But we also share the same Irish face: pale white skin,  big rectangular forehead, magnificent white hair swept straight back (OK, I’m still waiting on the “magnificent white” part), and beautiful blue eyes that (due to extreme nearsightedness) retreat so far into the head that we have no visible eyelids.

It’s the eyelids that inspired this post.  Their retreating fold makes them particularly prone to dermatitis.  I finally had to go to a dermatologist to get the appropriate cortisone to cure this extremely delicate skin area.  While I was in her office, she gave me the full body skin check.  After a lifetime of sunscreen, hats, and long sleeves, I am happy to report that my skin was all A-OK.  Even the freckles you can see in my first grade photo are long gone.

And I thought I was done needing to check for melanomas.  Nope — she said to come back in a year.  Turns out Parkis have a much higher risk of melanomas than the general population.  Why?  Don’t know – “More research is needed”.  However, one clue is that dopamine (that’s the stuff Parkis are low on) is high in melanin — so much so that the area of the brain where dopamine hangs out is called the “Substantia Nigra”  (“Dark Substance” – melanin is what gives our skin its color).

A Chinese review of 24 statistical studies on PD and melanoma totaled an impressively large number of PD patients (292,275 patients).. The total odds ratio was 1.83, which means (simplistically) that PD patients are 83% more likely to get melanoma than the general population. This does NOT mean that PD causes melanoma or vice versa – the study only indicates that PD correlates with melanoma in a statistically significant way. Repeat “Correlation Does Not Equal Causation” ten times.

Oddly (to me, anyway), another study concludes that Parkis have a lower occurrence than the general population of getting cancer — except for two kinds: melanoma and prostrate cancer.  The authors conclude that the findings in this study strongly support the hypothesis of a common genetic link between PD and melanoma.

 One more complication: Sinemet, the “artificial dopamine” (levodopa-carbidopa) taken by many Parkis, may exacerbate melanomas. Its FDA prescribing information includes this warning: “Because levodopa may activate a malignant melanoma, SINEMET should not be used in patients with suspicious, undiagnosed skin lesions or a history of melanoma.”
So, lather on that sunscreen, wear a hat, and put on that long sleeved shirt — good advice whether or not you have Parkinson’s.



About Laura Kennedy Gould

Author of "The Magic Trick -- Life with Parkinson's"
This entry was posted in Parkinson's Basics, Parkinson's People, Parkinson's Research, Side Effects and tagged , . Bookmark the permalink.

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