Researcher Says Increase in Melanoma Cases Isn't Just Due to Better Screening
WebMD Health News
Reviewed By Laura J. Martin, MD
March 9, 2010 (Miami Beach, Fla.) -- While some researchers suggest the rising rate melanoma may simply reflect a change in how doctors diagnose melanoma and the increased availability of skin cancer screenings, a leading dermatologist says the increase is real.
The average American's risk of developing melanoma in his or her lifetime increased from one in 1,500 in 1930, to one in 250 in 1980 and one in 74 in 2000, says Darrell S. Rigel, MD, clinical professor of dermatology at New York University Medical Center in New York City and a past president of the American Academy of Dermatology.
By 2004, a person had a one in 65 chance of getting the deadly skin cancer and now that risk is one in 58, Rigel says.
"If this rate continues to rise at the same pace, the risk will be one in 50 by 2015," he tells WebMD.
A total of 68,720 Americans were diagnosed with melanoma in 2009, compared with 47,700 in 2000, according to the CDC.
At the American Academy of Dermatology's annual meeting here, Rigel dispelled what he calls myths about the rise in melanoma.
Is Rise in Melanoma Due to Increased Surveillance?
Some studies have attributed the rise in melanoma to an increase in the number of skin cancer screenings.
If this was true, "you would expect cases to pop up earlier, and then suddenly drop off," Rigel says.
Take prostate cancer, for example, he says. There was a steep rise in prostate cancer diagnoses in the early 1990s, when testing for prostate specific antigen (PSA) was introduced, Rigel says. Rising PSA levels may signal prostate cancer.
Then, prostate cancer rates dropped dramatically from 1992-1995, after which they leveled off, he says.
"Until PSA testing was introduced, we had no way to detect early prostate cancers, before symptoms developed. With PSA testing, there was a transient increase in case due to increased detection of preclinical (before symptoms) disease. But once those initial cases of prostate cancer were found, it was not diagnosed as often," Rigel says.
Although skin cancer screenings became more readily accessible in the 1980s, no such trend is occurring with melanoma rates, Rigel says.
Is Rise in Melanoma Due to a Change in How Melanoma Is Diagnosed?
In a large international study, pathologists reviewed 2,665 pigmented lesions that had been originally been analyzed by pathologists from the 1930s to the 1980s. Their diagnoses matched, Rigel says.
Is Rise in Melanoma Due to Better Ways of Counting Cancer Cases?
The National Cancer Institute's method of counting cancer primarily relies on reports from hospitals about how many cancers are being seen in their institution each year, he says.
"So if we were better at counting cancer, you would expect rates of all cancers to go up, which is not the case," Rigel says.
In fact, melanoma is probably underreported, he says, as it is the only major cancer where patients are not seen in the hospital during the course of their disease.
"I often diagnose a patient in my office and excise the skin lesion in the office so the patient never even makes it to the hospital," he says.
A 1991 study, published in the Journal of the American Academy of Dermatology, showed that up to 19% of cases in Massachusetts were never reported. A 1997 study in the same journal showed a17% rate of underreporting in Iowa, Rigel adds.
Melanoma: Deaths vs. Survivals
Additional evidence for a real rise in melanoma cases comes from the fact that deaths from skin cancer are also on the rise, Rigel says. Yet at the same time, a patient's chance of surviving for at least five years from diagnosis is also on the rise.
If more people are dying of melanoma and more people are surviving melanoma, the only mathematical option is that cases are going up faster, he says.
Melanoma: Don't Become a Statistic
The bottom line, Rigel says, is "how the rise in melanoma affects our patients."
"We know the cause of melanoma is too much exposure to ultraviolet (UV) radiation, whether from the sun or indoor tanning beds and lamps. Simple behavior changes can lower your risk," he says.
So when should you see a doctor? If a mole is growing, bleeding, crusting, or changing, he says.
Harold S. Rabinovitz, MD, a dermatologist at the University of Miami Miller School of Medicine, says know your ABCs.
Look at your moles and check for:
- Asymmetry: one half unlike the other half.
- Border: irregular, scalloped or poorly defined.
- Color: varies from one area to another; shades of tan and brown, black; sometimes white, red or blue.
- Diameter: the size of a pencil eraser or larger.
- Evolving: changing in size, shape or color.
"A mole with any of these characteristics should be brought to a dermatologist's attention immediately," Rabinovitz says.
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Darrell S. Rigel, MD, past president, American Academy of Dermatology; clinical professor of dermatology, New York University Medical Center.
Harold S. Rabinovitz, MD, volunteer professor, department of dermatology, University of Miami Miller School of Medicine.
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