Changing Climate May Contribute to Increase in Skin Cancer

Leta Brown detected a brown spot on her leg that just wouldn’t go away. When the preschool teacher from Middletown, Maryland, finally went to see a doctor to check out the blotch she learned she had a tumor the size of a football.

Brown, a married mother of two, was diagnosed with metastic melanoma — the deadliest form of skin cancer.

“It was a really grim prognosis,” she said. “The doctors I saw at the time were sort of telling me to get my affairs in order.”

And the cancer was spreading.

“I also had tumors in my small intestines and in my lungs,” Brown said.

She believes it was likely caused by sun exposure and frequent sun burns as a child.

"We just didn't really use sunscreen when I was a kid,” she said. “It just wasn't really used widespread at the time, so I didn't even really think about being safe in the sun until I was older."

Exposure to UVB radiation from the sun causes non-melanoma skin cancer and is linked to increased risk of melanoma development, according to the National Cancer Institute. People with fair skin, like Brown, or who are sun-sensitive are at a higher risk of developing skin cancer, the federal agency said. Doctors have long warned of the dangers from overexposure to UV radiation after scientists first sounded the alarm on the human-induced depletion of Earth’s protective ozone layer. While studies show the ozone is finally healing from the damage 30 years later, its recovery is now being threatened by new emissions of banned ozone-depleting chemicals and a newly discovered link between climate change and ozone depletion.

According to the American Cancer Society, one in five Americans will develop skin cancer in their lifetime. The most common forms of skin cancer in the U.S. are basal cell and squamous cell, and usually treatable. Melanoma is less common and accounts for only 1% of all skin cancers but causes the vast majority of skin cancer deaths.

The ozone layer works as an atmospheric shield absorbing ultraviolet radiation from the sun, particularly harmful UVB rays. In the 1970s, scientists first realized that the use of chlorofluorocarbons (CFCs), man-made chemicals commonly used in aerosol sprays and refrigerator coolants, were eating away at the ozone and increasing the amount of UVB radiation that reaches the Earth’s surface.

By 1987, several countries, including the U.S., agreed in the Montreal Protocol to phase out CFCs and businesses were forced to come up with replacements for spray cans and other uses. As a result, the ozone began a decades-long process to heal from the damage, one that is now being threatened.

A study led by NOAA scientists and published in Nature in May 2018 found emissions of another banned ozone-depleting chemical, trichlorofluoromethane, or CFC-11, are on the rise and interfering with the recovery of Earth’s damaged ozone layer. Once commonly used as a foaming agent and in insulation, production of CFC-11 was supposed to have stopped as of 2010, according to the report. The illicit emissions are believed to be coming out of East Asia, the report noted.

"We're raising a flag to the global community to say, 'This is what's going on, and it is taking us away from timely recovery from ozone depletion,'" NOAA scientist Stephen Montzka, lead author of the report, said in a new release.

To make matters worse, new research has linked for the first time climate change and ozone depletion. James Anderson, an atmospheric chemist at Harvard University in Cambridge, Massachusetts, and his colleagues found that powerful summer thunderstorms in the Great Plains region inject water vapor far higher into the stratosphere than previously believed, where the moisture triggers the same type of ozone-depleting chemical reaction that occurs over the polar regions and causes the ozone hole. Climate change could be an underlying cause because it can supercharge summertime thunderstorms. Global warming feeds warmth and moisture into the atmosphere, and that fuels instability, Anderson said in a news release announcing the study’s findings.

"If you were to ask me where this fits into the spectrum of things I worry about, right now it's at the top of the list," Anderson said in a news release. "What this research does is connect, for the first time, climate change with ozone depletion, and ozone loss is directly tied to increases in skin cancer incidence, because more ultraviolet radiation is penetrating the atmosphere."

The prevalence of melanoma has rapidly increased over the past 30 years, studies show. The ACS estimates in 2019, 96,480 new cases of melanoma will be diagnosed in the U.S. and the disease is expected to cause more than 7,000 deaths. And while the rise in skin cancer is likely due to UV exposure, studies have also “attributed the rising incidence of melanoma to an increase in diagnostic scrutiny rather than an actual increase in the incidence of disease,” according to the National Institute of Health. Still, the World Health Organization predicts a 10% increase in skin cancer incidence among the U.S. population by 2050.

The American Cancer Society recommends avoiding the sun, especially between 10 a.m. and 4 p.m., and says don’t allow yourself to get sunburned in order to lower the risk of melanoma. The group also warns against using tanning beds and advises to wear protective clothing like pants, long-sleeve shirts, hats and sunglasses when possible. Use a broad spectrum (UVA/UVB) sunscreen with an SPF of 15 or higher every day. For extended outdoor activity, the group suggests using a water-resistant, broad spectrum sunscreen with an SPF of 30 or higher and reapply it every two hours or after swimming or sweating. Examine your skin from head-to-toe every month and if you notice a new or changing mole, contact a dermatologist immediately to get it checked out.

Leta Brown, meanwhile, remains cancer free six years after her diagnosis thanks to advances in cancer treatment. Brown signed up for an immunotherapy clinical trial at Georgetown's Lombardi Comprehensive Cancer Center in 2013. Three to four months into the clinical trial, Brown said there was no evidence of disease. The treatment regimen for advanced melanoma has since been approved by the FDA.

“That really has taken this cancer that had only a 10 percent chance of people being alive at two years and changing that chance of survival to 60, 70 or, in our heads, 80 percent,” said Dr. Michael Atkins, deputy director of the center.

The disease took a toll on Brown’s body. She walks with a brace after suffering nerve damage from surgery, and the cancer drugs had some side effects, too.

But she's grateful.

“I hope the reason why I was able to have all of this good fortune will manifest in some way that I am able to serve other people,” she said.