September 20, 2012

Parkinson's, Genealogy and Risk of Prostate Cancer and Melanoma

After a week of posting about our miserable political system, it's a relief to get back to the real world of dealing with Parkinson's and aging and an aching back. Tackling these issues isn't as depressing as our politics. (I'm only half joking.)

Here's a just released study that I found interesting:

A recent study from Archives of Neurology suggests that people with Parkinson's disease (PD) may carry a higher risk for both melanoma (a form of skin cancer) and prostate cancer. I guess I'm Exhibit A, since I have PD and prostate cancer. I've also been treated twice for melanoma.

According to the research paper, the risk runs both ways. Those with PD have an increased risk of prostate cancer and those with prostate cancer have an increased risk of PD. The study analyzed the Utah Population Database, which includes personal and family information for over two million individuals. Amazingly, some of those records provide family information for more than 15 generations.

Here's a summary of the findings:
  • An increased risk for PD was associated with an increased risk for both prostate cancer and melanoma.
  • Prostate cancer was diagnosed in 212 individuals who died with PD, compared with a normal expected risk of only 124.
  • There was elevated risk for prostate cancer among first-, second-, and third-degree relatives of people who died with Parkinson's disease.
  • There was significantly increased risk of death from PD among 22,147 men with a diagnosis of prostate cancer.
  • Melanoma and prostate cancer were the only cancers in significant excess among those with PD. Colorectal, lung, pancreas, and stomach cancers were observed at lower than expected rates.
Note: Statistical analyses like these only show an association and do not prove cause and effect.

PD and Melanoma
The reported link between melanoma and PD is not new. For years, researchers have noted that people with PD carry a higher risk for melanoma. They've also debated whether that elevated risk is caused by having PD or taking levodopa, the gold-standard therapy for the disease. The Michael J. Fox Foundation (MJFF) has funded research to further investigate this association. 

In a 2010 interview with MJFF, Susan Bressman, chairman of the department of neurology at Beth Israel Center, explained why levodopa might make someone more likely to develop melanoma:
Levodopa is needed to make the skin pigment melanin. So it makes sense that if you introduce excess levodopa into the system or hype up the system in any way, you could increase risk for melanoma. The usual precaution a neurologist would take for a patient with a history of melanoma is to be cautious about treatment with dopaminergics.
Still, according to Bressman, recent studies have found that having PD causes the melanoma risk, not taking the drugs. While the jury is still out on what causes the PD-melanoma link, PD patients and their doctors should always be vigilant for signs of skin cancer.

I'll continue my annual checkups with my dermatologist. And I'll resolve, once again, to wear a cap and apply sunscreen when I go outside.

PD and Prostate Cancer
I just had my semi-annual checkup with my urologist yesterday and should receive my latest PSA report Friday. After 15 years of slowly increasing PSA numbers, I saw my PSA reading more than double last September. Then it dropped significantly in March. I asked my urologist yesterday if that unusual spike could be related to the trauma from my car crash in August. He said that the accident might be a factor, since urologists have speculated that stress may affect PSA levels. There's another reason I'm especially interested:  I've been taking curcumin for several months. Studies suggest that curcumin slows the progress of cancers in general, and prostate cancer in particular.

Watch this space next week for an update.

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