A one-county study promoted by Mayo Clinic dermatologists in early April spawned headlines in the national news media suggesting that melanoma is increasing faster in women than it is in men — a false conclusion the study’s own data didn’t show, didn’t even measure and one that conflicts with data from the nation’s largest cancer registry.

Melanoma is nearly twice as common in men and is increasing fastest in men over age 50 worldwide. So why no attempt to correct that mis-reporting?

“Given the number of stories written about the Mayo study, and the fact that it appears Mayo has not attempted to correct the reports, one has to consider that it’s possible the Mayo doctors intended to mislead the press,” Smart Tan Vice President Joseph Levy said. “Allowing the press to report that melanoma is more common in women than it is in men is totally irresponsible. Older men, who are decidedly the most at risk, are now being told that they aren’t.”

Mayo’s study — looking at data from Olmsted County, Minn., from 1970-2010 — reported that county’s melanoma rates for 18-39 year-olds without even reporting rates for other age groups — an omission that makes it hard to explain how one could believe this paper showed that the increase was greatest in this age group. The conclusions the paper did report conflicted the National Cancer Institute’s much-larger nationwide Cancer database. The National Cancer Institute’s much-larger melanoma database shows two things conclusively:

1. Melanoma incidence has increased more in men than in women since 1970.
2. Melanoma mortality has declined in women since the mid-1980s.

“The Mayo doctors have attempted to say that the National Cancer Institute’s database under-reports cases. It’s amazing that the national media allowed this explanation,” Levy said. Under-reporting cannot explain why NCI shows a different trend entirely. That’s mathematically impossible. Under-reporting can translate a curve downward, but cannot change the direction of the curve.”

Many papers in peer-reviewed journals have also reported that it is statistically impossible for cancer incidence rates to increase if mortality rates aren’t and that reported melanoma incidence increases are most-likely explained by this.

In promoting their study, the Mayo Dermatology group did not even acknowledge this possible explanation, an explanation that should be the default theory, but instead blamed the increase in their data on indoor tanning — a variable the study did not even measure.

Here is United Press International’s story about the May study — one of many that falsely suggests melanoma is increasing faster in men than in women.

Here is Smart Tan’s response to the Mayo study, as sent to the media.