Dr. A. Bernard Ackerman, a dermatologist, spends much of his time diagnosing the potentially deadly cancer melanoma and other skin diseases.
But when he returned from a recent trip to Israel, he was, well, deeply tanned.
Burnished brown, in fact.
Dr. Ackerman did not use sunscreen on his trip. He did not give any thought to the hundreds of moles that speckle his body. He did not even put a hat on his bald head.
Other dermatologists may worry about getting melanoma from exposure to ultraviolet rays. But Dr. Ackerman, 67, a renowned expert in the field and the emeritus director of the Ackerman Academy of Dermatopathology in New York, said the link between melanoma and sun exposure was ”not proven.”
He has scrutinized, one by one, the widely held precepts about melanoma and the sun, and found the evidence wanting. ”The field is just replete with nonsense,” he said.
For example, it is commonly assumed that painful or blistering sunburns early in life set the stage for the skin cancer later on. But while some studies show a small association, Dr. Ackerman says, others show none. And even studies that do show an effect disagree on when the danger period for sunburns is supposed to be.
Taken as a whole, Dr. Ackerman argues, the research is inconsistent and fails to make the case.
Common wisdom also has it that sunscreens protect against melanoma. But Dr. Ackerman points to a recent editorial in the journal Archives of Dermatology concluding that there was no evidence to support that idea.
Finally, many people assert that the more intense a person’s sun exposure, the greater the risk of melanoma.
For example, Dr. Darrell S. Rigel, a New York dermatologist, points out that the incidence of melanoma increases as distance to the equator decreases. Dr. Rigel, a past president of the American Academy of Dermatology and the lead editor of ”Cancer of the Skin,” a major textbook in the field, cites this as a compelling reason to conclude that sun exposure causes the skin cancer.
But it is not compelling to Dr. Ackerman. Epidemiological data on melanoma, he says, are imprecise and inaccurate. In searching for the causes of other cancers, he argues, epidemiological data have led researchers astray, and by their nature they cannot demonstrate cause and effect.
Stay out of the sun, Dr. Ackerman advises, but do it to avoid premature aging of the skin. If you are very fair, avoiding sunlight will also help prevent squamous cell carcinoma, a less dangerous cancer. But it would be a mistake, he says, to assume that avoiding sunlight or using sunscreens will offer protection from melanoma.
Dr. Ackerman has been enamored of the skin and its diseases since his earliest days as a resident at Columbia. Studying dermatology, to him, was like taking courses in art history. ”If you know a certain artist you can recognize him again,” he said. ”So it is with lesions in the skin. A lesion is like a painting or a piece of sculpture.”
He has spent most of his career in academia and has published 625 research papers. His list of honors and awards includes this year’s the Master Award, given to one person a year by the American Academy of Dermatology.
In 1999 he started his own academy, supported by AmeriPath, a company that owns pathology laboratories. ”I had nothing to sell — I was always in university life,” Dr. Ackerman said. ”If you’ll excuse the expression and not think I’m a tart, they bought me.”
His academy, he says, is now the world’s largest training center for dermatopathology. Dr. Ackerman, who is paid a flat salary, and his six associates examine more than 100,000 specimens and have done more than 4,000 consultations each year. Dr. Ackerman continues to teach and write, and also to ask for data and question his field’s conventional wisdom.
Challenging the link between sun and melanoma is part of this pattern.
Dr. Ackerman even questions whether the ”epidemic” of melanoma proclaimed by many dermatologists exists. The definition of the cancer, he says, has changed over time, leading doctors to diagnose, remove and cure cancerous growths that once would not have been called melanoma.
”The criteria today, clinically and histopathologically, are diametrically different from those 30 years ago,” he said. In medical school, he continued, ”we were taught that melanoma is a big, black, fungating tumor that kills. Who would have believed then that you can recognize melanoma for what it is when it is small and flat and the size of the fingernail on your pinky? You would have said they were insane.”
Anyone who argues that sun exposure causes melanoma, Dr. Ackerman says, needs to explain why blacks and Asians get melanoma almost exclusively on skin that is not exposed to sunlight: the palms, soles, nails and mucous membranes. Even in whites, the most common melanoma sites — the leg in women, the trunk in men — are hardly the most sun-exposed body parts.
It is not a popular argument. Dr. Rigel, reached by telephone in Hawaii, where he was vacationing, said it was perverse of Dr. Ackerman to pick the data apart.
Melanoma, Dr. Rigel said, can occur ”where the sun doesn’t shine.” But that is because sunlight suppresses immune cells in the skin’s surface that ordinarily hold cancer at bay, he said.
He himself stays pale, even in Hawaii, that land of intense sunlight.
”I’m a dermatologist,” he explained.
Dr. Ackerman does not buy the immune-system argument. It is a hypothesis to support the hypothesis that sun exposure causes melanoma, he says. But it is not evidence.
Of course, Dr. Ackerman adds, he could be wrong.
”If the evidence were compelling, I’d be the first to capitulate,” he said. ”I’d say: ‘I tip my hat to you. Well done.”’
Original At: nytimes.com