I think about that guy every spring when the Skin Cancer Foundation (SCF) makes its annual appeal to the public to use sunscreen. As people heed their warning this year, few will remember the report that made headlines in February. According to a survey of new research by epidemiologist Marianne Berwick of the Memorial Sloan-Kettering Cancer Center in New York, there is no evidence that sunscreen offers any real protection against malignant melanoma, the most dangerous form of skin cancer. "It's not safe to rely on sunscreen," Berwick told the press.
The SCF promptly refuted her findings in a press release, telling consumers that "sunscreen should continue to be an integral part of a comprehensive program" to prevent melanoma. That's what most people will likely hear from their dermatologists as well. What they won't learn is that dermatologists get much of their information from the SCF, and the SCF, in turn, is heavily supported by the sunscreen industry. (A sunscreen manufacturer even funded SCF's quarterly consumer publication, "Sun and Skin News.") No wonder the foundation doesn't give much credence to the growing number of studies showing that even so-called broad-spectrum sunscreen doesn't prevent melanoma. Like the road-destroying trucks that guaranteed work for the concrete company, rising melanoma rates scare people into using more sunscreen.
In a 1993 Mother Jones article ("Beach Bummer," May/June), I reported that sunscreen may actually contribute to skin cancer. It prolongs people's time in the sun by preventing the only natural melanoma warning system human skin hassunburn. Berwick didn't go that far, but in noting the mounting evidence against sunscreen, she credited Mother Jones for its reporting.
What's changed in the five years since our report? More studies prove this link, melanoma rates are rising about 6 percent each year, and sunscreen sales are continuing to climb.
Sunscreen makers and the SCF have engaged in a cynical sleight of hand by claiming that sunscreen helps prevent skin cancer. There are three main kinds of skin cancer: basal cell, squamous cell, and malignant melanoma. The first two are common (about 1 million cases a year) and almost always medically minor. The American Cancer Society and the National Cancer Institute don't even count them in the nation's cancer statistics. Melanoma is much less common (40,300 diagnoses last year), but often fatal (7,300 deaths).
Basal cell and squamous cell skin cancer are caused primarily by UV-B light, the kind that causes sunburn, and there's credible evidence that sunscreen helps prevent those two types of cancer (as well as offers protection against premature aging of skin). The Food and Drug Administration's SPF (or sun protection factor) rating program measures UV-B protection. But most sunscreens do not offer protection against UV-A, the harmful, longer-wavelength UV light. UV-A penetrates right through the outer skinand through sunscreendown to the melanocytes, the cells that become cancerous in melanoma cases. In one study that proved this point, researchers at the Brookhaven National Laboratory in Upton, New York, induced melanoma in fish by exposing them to both UV-B and UV-A sunlight. They concluded: "Sunscreens effective in the UV-B region...would not protect against melanoma."
But when people hear the term skin cancer, they think melanoma. That's because when sunscreen labels claim that the product can protect people from skin cancer, consumers don't differentiate melanoma from basal cell and squamous cell skin cancers.
Until around 1950, melanoma was rare. then its incidence increased slowly until the mid-1960s, when it accelerated into the current epidemic. The standard, pro-sunscreen explanation is that, like lung cancer, the disease has a long lag time, on the order of 20 years. Americans began sunbathing in earnest in the 1950s, and as a result, the melanoma epidemic hit in the 1970s. But even a cursory look at the history of sunbathing washes this explanation away faster than a sand castle in a hurricane. Ask any elderly person you know. Beaches around the country were jammed on summer weekends in the 1930s. Why didn't a melanoma epidemic hit the Depression generation 20 years later? Why did it take until the mid-1970s for the epidemic to strike? Sunscreen promoters offer no clue.
Meanwhile, ever since the melanoma rate began soaring, health authorities have exhorted us to use sunscreen. Americans have clearly taken this advice to heart. Sales figures jumped from $18 million in 1972 to $500 million in 1996. If melanoma has a 20-year lag time and sunscreen is protective, the melanoma rate should have started to level off by now. Instead, it's climbing. In 1980, an American's lifetime melanoma risk was 1 in 250. Today, it's 1 in 84.
Now take a closer look at the presumption that melanoma has a long lag time. The research indicates that the lag time could be as low as two years. Lung cancer, heart disease, and other conditions with long lag times are diagnosed at a steady rate year-round. Summer brings no more diagnoses than winter because over, say, 20 years, seasonal distinctions blur. Melanoma diagnoses, on the other hand, do reflect seasonality. At least five studies of melanoma (in Hawaii, the continental U.S., Sweden, Norway, and England and Wales) all agree that melanoma diagnoses follow a seasonal pattern, showing up at a considerably higher rate in summer than in winter. Seasonality is a hallmark of biological events with short lag times.
Given that melanoma was rare until 1950, and that melanoma may have a lag time of only two to five years, then something about our relationship with UV light must have changed a few years before the melanoma rate began inching up in the early 1950s.
Consider sunscreen. It was first introduced in the early 1940s as tanning lotion. The idea was that if you could stay in the sun without burning, you'd tan. A few years later, the melanoma rate began to rise. Improved tanning lotions came on the market in the early 1960s, and a few years after that, the melanoma rate zoomed up. Public health authorities became concerned, and melanoma became news. Seeing a commercial opportunity, the makers of tanning lotions repositioned their products as "sunscreen," and the now familiar sermonizing began. Since then, melanoma has become the nation's fastest-rising cancer and sunscreen sales have continued to climb. Ozone depletion may play a role in the higher melanoma rate, as some scientists say, but melanoma cases began to go up long before ozone depletion became an issue.
In recent years, it has become clear that to prevent melanoma, sunscreen must do more than block UV-B raysit must also protect against UV-A. As a result, sunscreen makers have tinkered with their formulas, and now most claim that their products provide broad-spectrum UV-A and UV-B coverage. Sounds good, but it's actually another sleight of hand on the part of sunscreen manufacturers. Only one ingredient, avobenzone, is "clearly proven" to block UV-A sunlight, and according to FDA spokeswoman Ivy Kupec, the FDA doesn't require its inclusion in sunscreens in order for manufacturers to claim that their products offer broad-spectrum protection. ("I guess there's an inconsistency," she notes.) Kupec added that manufacturers "could still say [their product] protects against UV-A, because they can do it until we tell them not to." So much for regulatory protection.
Even if sunscreen blocked UV-A completely, almost no one uses it in the way that grants real protection against sunburn. For sunscreen to live up to its hype, you have to slop it on real thick and reapply it every few hours. We're talking at least one full bottle per person per day at the beach. Meanwhile, the vast majority of sunscreen users apply a thin layer once or twice.
The only proven way to prevent melanoma is to cover up. Our forebears did so in the days before sunscreen. Clearly it worked because melanoma was so rare. It's also what people now do in Australia. White Australians come largely from light-skinned British/Irish stock. Queensland province, in northeastern Australia, has the highest melanoma rate in the world, but as the SCF proudly pointed out when it rebutted Berwick's study, melanoma rates there have started to flatten. What the SCF did not mention is that while the Queensland public health authorities began a big-budget PR campaign promoting sunscreen in 1981, they shifted the campaign's focus a few years ago to strongly encourage people to cover up and stay in the shade.
The Skin Cancer Foundation does acknowledge that sunscreen alone is not enough. You need to wear protective clothing (pricey new fabrics such as Solumbra apparently block both UV-A and UV-B, but a wide hat and long, lightweight summer clothing should suffice), and spend more time in the shade. If you're a beach lover, invest in a sun umbrella. But think twice before you slap on sunscreen. Some cement mixers destroy the roads we're told they build. And some products may contribute to the cancer we're told they prevent.
Additional reporting by Kate Rope.