Ackerman, who has a place in Miami Beach during the winter and reads in New York's Central Park spring, summer and fall, is covered with solar lentigines -- brown blotches caused by sunlight.
His book, just released in its second edition, comes as melanoma scientists push back against media campaigns by the indoor tanning lobby, and influential medical journals such as the British Medical Journal publish debates about whether sun exposure is a major cause of melanoma.
On one side are experts who argue UV radiation is essential for the development of the disease, who say the willingness of people to expose themselves to "the most ubiquitous" carcinogen known to man suggests tanning might be addictive -- that the skin responds to UV radiation by producing hormones that trigger feelings of euphoria, giving people a "high" from being in the sun.
On the other side are researchers who say that while there is solid evidence UV rays cause non-melanoma skin cancers and leave skin wrinkled, battered and grooved by photo damage, the effect on the risk of melanoma has been overstated.
Ackerman says warnings issued again as recently as
September by U. S. researchers that there is no such thing as a safe tan "are pure bunk."
"Now, it is true that if you bake in the sun for decades, you not only have a tan, but you have damage to the dermis." But if a disease is brought into being by sunlight, Ackerman argues, it must be confined to sun-exposed sites, and the lesions must be numerous.
"In Asians and Africans [melanoma] never occurs on a sun exposed site, for practical purposes," Ackerman said in an interview. Rather, he says, it occurs almost entirely on the palms of the hands and soles of the feet.
"In Caucasians, it occurs mostly on covered sites -- the trunk, the back." As well, he says most people diagnosed with melanoma get one lesion. "And if somebody has more than one it's usually two, maybe three."
Ackerman says that, "of course there are risks associated with exposure to sunlight." No one should get a burn, and fair-skinned, blue-eyed blonds are particularly vulnerable. As well, he says, the sun can cause melanoma and other skin cancers in people who are genetically susceptible to get them.
But Ackerman says the number of melanomas hasn't changed; rather, more diagnoses are being made because of heightened vigilance. Dr. Gregory Daniels is an expert in melanoma at the Moore Cancer Center at the University of California, San Diego. He believes there probably is a link between sun exposure and melanoma. "The danger
is we think we understand it."
"Why is it that melanoma went from something that happened to one in 5,000 people in the 1930s, to one in 50?" Daniels says. "What is that? What changed? Fluorescent lights? We're now staying indoors more. We just don't know. The problem is we don't know, but we think we do.
"So what we do is we get rid of our chronic sun exposure and we've now become a group of people that now have induced, intermittent exposure, because we forget. We go outside, we don't have sunscreen on those one or two days a month. And it may be that intermitted exposure is bad and having chronic low level exposure is protective."
He said non-melanoma skin cancers, the more common, less deadly ones, are linked to more sun exposure. "These happen as we age, they happen on sun-exposed areas. More sun equals more of these things."
If there were a connection, it would stand to reason that melanomas would occur at burn sites. But "there is no evidence for this," Dr. Sam Shuster, of the department of dermatology at Norfolk and Norwich University Hospital, wrote in the British Medical Journal in July. Sunburn occurs in sun-exposed sites, he says, "and these are not the sites at which melanomas occur."
But a month later, a paper published in Pigment Cell & Melanoma Research called UV exposure "the most ubiquitous human carcinogen" and an essential risk factor for the development of melanoma.
"What it suggests is that when ultra violet radiation causes a tan, it almost certainly has done so through a process of damaging DNA, and mutating DNA, meaning intrinsically that it was simultaneously increasing the risk of developing skin cancer," says Dr. David Fisher, chair of the department of dermatology and director of the melanoma program in medical oncology at Massachusetts General Hospital.
Human skin cells are considerably adept at repairing this damage, Fisher says. But he says that repair process is imperfect and that the more people expose themselves to UV radiation, the greater the chance, statistically, that the process won't repair every lesion.
One thing is clear: A diagnosis of melanoma, Daniels says, "scares the sh--out of people." Most people are diagnosed with very early stage melanoma and cured. But current therapies are not effective in curing melanoma once it has spread.
