One in 54 people in the United States will be diagnosed with invasive melanoma, according to new data from 2016.
Melanoma rates have been rising in the U.S. for the last two decades. No one knows why, but one possible explanation is the increasing use of erectile dysfunction drugs since the 1990s.
Eli Lilly & Co. and Pfizer are facing hundreds of lawsuits for failing to warn that Cialis and Viagra might cause or exacerbate melanoma.
Federal judges have centralized the lawsuits under U.S. District Judge Richard Seeborg in the Northern District of California — Multi-District Litigation (MDL No. 2691).
Like a class action, MDLs improve efficiency and help lawyers coordinate testimony, trials, and settlements. Unlike a class action, each case remains independent.
Nearly 250 lawsuits involving Viagra were already pending in the MDL. Judges added Cialis cases because they are so similar.
Cialis, Viagra, and Levitra all work by blocking a natural substance in the body called PDE5. This relaxes blood vessels and increases blood-flow to the penis, which treats erectile dysfunction.
About 50% of melanomas also naturally block PDE5. Studies have shown these cancers to be more aggressive and likely to spread.
So when researchers decided to investigate if an erectile-dysfunction medication that blocked PDE5 also made melanoma more aggressive, the results were not surprising.
Viagra was linked to an 84% increased risk of melanoma — nearly double the risk of men who did not use Viagra — in a study of 25,000 men by researchers at Harvard Medical School in 2014.
Their findings are supported by another study from 2011, in which researchers concluded that blocking PDE5 caused a “dramatic increase in melanoma cell invasion.”
The studies do not prove that Cialis or Viagra cause melanoma. The biggest risk-factors for melanoma are cumulative age and sun exposure. Older men who can afford to buy Viagra can also afford more sunny vacations, which would also explain the correlation.
Even so, melanoma is the deadliest type of skin cancer. Many men say Pfizer and Eli Lilly should have warned them about the possible risk as evidence emerged.
Melanoma is less common than other types of skin cancer, but far more dangerous. In its early stages, melanoma looks like a mole, and it can be cured with a simple surgery. The problem is that melanoma is often ignored until it is too late.
Source: “Melanoma skin cancer diagnoses, deaths steadily climbing” — CBS News, December 2016