The nation is in the grip of what looks like a terrifying melanoma epidemic: melanoma is being diagnosed at more than double the rate it was in 1986, increasing faster than any other major cancer.
But why the numbers are increasing is a contentious subject, so touchy that one dermatologist called it "the third rail of dermatology."
Many dermatologists argue that melanoma, the most deadly of the skin cancers, is in fact becoming more common. And they recommend regular skin cancer screening as the best way to save lives. But some specialists say that what the numbers represent is not an epidemic of skin cancer but an epidemic of skin cancer screening, and a new study lends support to this view.
In the study, published in the current issue of The British Medical Journal, Dr. H. Gilbert Welch of the Department of Veterans Affairs in White River Junction, Vt., and Dartmouth Medical School and his colleagues analyzed melanoma's changing incidence and death rate over time.
The researchers used Medicare data to track the swift rise in melanoma cases since 1986 and data compiled by the National Cancer Institute to track the death rate and the number of people with early and late-stage disease.
They found that since 1986, skin biopsies have risen by 250 percent, a figure nearly the same as the rise in the incidence of early stage melanoma. But there was no change in the melanoma death rate. And the incidence of advanced disease also did not change, the researchers found.
Dr. Welch and two colleagues, Dr. Steven Woloshin and Dr. Lisa M. Schwartz, argue that if there was really an epidemic of melanoma - for example, if something in the environment was causing people to get the skin cancer, scientists should see increases in cancers at all stages. This is what happened with lung cancer caused by smoking, and with other cancers caused by toxic substances.
The fact that the increase was seen only in very early stage disease was a tip-off that the epidemic might be less than it seemed, Dr. Welch said.
And that, he says, leads to a difficult question. The point of screening for melanoma is to reduce the death toll from the cancer. But if screening has not altered the number of patients with advanced disease or lowered the death rate, what is its benefit?
"That's the million dollar question," Dr. Welch said. "It certainly raises questions about whether we're doing any good."
The researchers hastened to add that people who notice suspicious moles or spots should not hesitate to see a doctor. But skin cancer screening, they said, is directed at healthy people who have no reason to suspect that anything is wrong.
The federal Preventative Services Task Force, which makes screening recommendations, has said that there was insufficient evidence to recommend either for or against skin screening.
But the American Cancer Society recommends regular skin screening, as does the American Academy of Dermatology, which sponsors Melanoma Mondays and free skin screening clinics that see more than 200,00 people a year.
Speaking for the dermatology academy, one of its past presidents, Dr. Darrell Rigel, a dermatologist in New York, said it only made sense to look for melanomas and remove them before they spread. "As dermatologists, we see people die every day from melanoma," he said. "And there's another thing we know with melanoma that's very clear. The earlier you find it and treat it, the better the survival."
More and more people are having skin biopsies, Dr. Rigel said, but he questioned Dr. Welch's conclusion that the biopsies were leading to excessive diagnoses of melanoma. "I would say the inverse is more likely," Dr. Rigel said. "There are more melanomas and therefore more biopsies."
At the American Cancer Society, Dr. Len Lichtenfeld, an oncologist, said his group reviewed the same data as Dr. Welch and came to a different conclusion. Screening, he said, appears to be saving lives.
As evidence Dr. Lichtenfeld pointed to a trend in the data indicating that the death rate from the disease rose slightly year by year until about a decade ago. That is consistent with an increase in serious cases of melanoma.
Now, he said, "there has been a suggestion in the data that the death rates in the Medicare age group are going down," an effect that would be expected if screening was working.
He added, "We agree that some of the melanomas are biologically indolent, but we also feel that when we look at the trend in the data and the suggestion of decreased mortality that there has been a benefit from increased surveillance for the disease."
Dr. Welch disagrees. He said the cancer society was "taking tiny, tiny differences" in death rates from year to year and "putting a huge microscope on it."
In fact, he said, the death rate has been basically flat since 1986, although it bounces around slightly from year to year as a result of statistical fluctuations.
"We don't disagree about the data," Dr. Welch said. "We disagree about the interpretation. We are not arguing that there is zero change in disease burden. We are arguing that most of the newly diagnosed cases are the result of increased screening."
In a 1997 article, two dermatologists, Dr. Robert Swerlick and Dr. Suephy Chen of Emory University and the Atlanta Veterans Affairs Medical Center, wrote that while some people might be saved by screening, there also are risks from a melanoma diagnosis.
"After a patient has received the diagnosis of melanoma, obtaining insurance can be extremely difficult," they wrote. "The diagnosis of melanoma also results in heightened scrutiny of all first-degree relatives and family members of the patient, and if increased surveillance leads to increased diagnosis, this process may also put them at risk for the diagnosis of melanoma."
Others who study cancer screening said that Dr. Welch's arguments were convincing and that he had raised issues about the national melanoma epidemic that could not easily be dismissed.
Dr. Barnett Kramer, associate director of the Office of Disease Prevention at the National Institutes of Health, said that, of course, the ideal way to know if a screening program works is to do a randomized clinical trial, assigning some people to screening and not others, then seeing if the screening saved lives. Absent such a study, he said, he finds Dr. Welch's paper convincing.
"It's doesn't look like our melanoma awareness campaigns have made an impact on mortality or on late-stage disease," Dr. Kramer said.
Dr. Russell Harris, a professor of medicine at the University of North Carolina and a member of the Preventive Services Task Force, said the new paper "should certainly make us worry about screening."
That also is the view of Dr. A. Bernard Ackerman, emeritus director of the Ackerman Academy of Dermatopathology in New York. Dermatologists have gone too far, he said, with screening clinics, removing innocuous moles and diagnosing melanoma too freely.
It makes sense for a doctor to look at your skin during a regular physical exam, Dr. Ackerman said, but screening programs have led to an excessive zeal for skin biopsies and for diagnosing melanoma.
"There has been a mania for taking off these moles that are of no consequence," Dr. Ackerman said. "We're talking about billions and billions of dollars being spent, based on hype."
While there may be questions about screening programs, Dr. Swerlick said that few in his field wanted to discussion their merits. He and Dr. Chen tried to open the debate themselves a few years ago but were met with hostility or disdain, he said.
"My colleagues in private practice know what we have written and they can't imagine that it could be correct," Dr. Swerlick said.
"This is a very touchy subject," he added.
And he appreciates why. "Many well-intentioned people have focused their clinical careers on this," he said, "and I can understand how unnerving it might be to be faced with the prospect that their efforts have been directed toward something ineffectual."
For his part, Dr. Welch says that early detection "is a double-edged sword and people need to remember that."
A few people might be saved because a cancer is found early, he said, but many, many more will be thrown into the medical mill when there is nothing wrong with them.
"People should realize that is the price we pay for screening," Dr. Welch said, and although screening is widely promoted, "we ought to know whether it helps."
