Melanoma: Reports of the Epidemic are Greatly Exaggerated.

The type of skin cancer called malignant melanoma is the fastest growing cancer in the UK, and is increasing in the US, and in Australia.  In the UK, malignant melanoma strikes 13.4 out of 100,000 men per year and 14.7 out of 100,000 women per year.  Of those people who are diagnosed with malignant melanoma, approximately 23% of men and 15% of women will die from the disease. 

The increase in diagnosis of malignant melanoma started in the 1970s and continues four decades later, but the rate of death from malignant melanoma leveled off in the 1990s, according to Garbe et al.  And Levell et al report that while the rate of diagnosis of all malignant melanoma has been increasing, this increase is wholly represented by minimal stage 1 disease.  This is interpreted to mean that there has been a so-called diagnostic drift; funny moles that would have been diagnosed as simply funny moles 30 years ago are now being diagnosed, and possibly over- or misdiagnosed as early melanoma.  If you think about it, the fact that the increase in early diagnosis of melanoma has not led to a decrease in the total death rate from melanoma probably supports the conclusion that these extra minimal stage 1 disease lesions are not melanoma at all. 

Diagnostic drift has also been targeted as the cause of an apparent increase in primary liver cancer, and an apparent increase in acute myocardial infarction (heart attack) that occurs in hospitals. 

Please read our legal disclaimer.

Write a comment

Name:
Email:*
Subject:
Comment:*

I would like to receive news and updates from MedPie.com Yes No

Help prevent spam - enter security code above:
 

block
Posts: 1

This Story Picked Up by the New York Times
Reply #1 on : Tue September 29, 2009, 12:48:44

---

On September 28, eleven days after this article appeared, the New York times published a story on the diagnostic drift of malignant melanoma: http://www.nytimes.com/2009/09/29/health/29mela.html?_r=1&hpw

There was no opportunity to comment on that article, but there was a significant error. The author misinterprets Dr. Rigel's statement that the absolute number of melanomas diagnosed is rising to mean that "The death rate from melanoma has also been going up, Dr. Rigel said, but so has the survival rate."

A rate can be thought of as a percentage. If the percentage of patients who die from melanoma goes up, the percentage of patients who survive melanoma MUST go down (you can't exceed 100%, of course). What Dr. Rigel undoubtedly said was that the absolute (total, not percentage) of patients who are dying of melanoma was going up, at the same time that the absolute number of patients who survive melanoma is going up.

This is a critical difference, and shows how important medical concepts are reported in error even in the best news organizations in the world.

Sponsored Links