By Jenifer Goodwin
MONDAY, March 15 (HealthDay News) -- The incidence of non-melanoma skin cancer has steadily increased since the 1990s, making it by far the most common form of cancer, affecting more people than all other cancers combined, two new studies find.
More than 2 million Americans on Medicare were treated for non-melanoma skin cancer in 2006, up from 1.6 million in 1992, according to one study. The other found that one in five 70-year-olds has been treated for non-melanoma skin cancer.
Researchers called non-melanoma skin cancer an "epidemic" that is only going to get worse as all those bathing beauties and sun worshippers from the 1960s, 1970s and 1980s get older, and their cumulative sun exposure racks up.
"We are dealing with a problem that is not going away," said Dr. Howard Rogers, a dermatologist in Norwich, Conn., and lead author of one of the studies. "The number has kept going up and up at a rate of 4.2 percent every year, on average, from 1992 to 2006," he said.
The studies are published in the March issue of the Archives of Dermatology.
The two types of non-melanoma skin cancer are basal cell and squamous cell. While basal cell carcinoma is slow-growing and rarely fatal, it can damage the surrounding tissue and bone if it's not caught early, causing disfigurement when the cancer is removed.
Squamous cell carcinoma is also rarely fatal, though it can metastasize and spread to the lymph nodes and other organs, Rogers said. When caught early, squamous cell carcinomas are also highly treatable.
In the study by Rogers and colleagues, the researchers analyzed data from two Medicare databases and national surveys. They found the total number of procedures to treat skin cancer in the Medicare population increased by nearly 77 percent between 1992 and 2006. Between 2002 and 2006 alone, skin cancer procedures increased by 16 percent.
In the second study, Dr. Robert Stern of Beth Israel Deaconess Medical Center and Harvard Medical School in Boston, developed a mathematical model to estimate the prevalence of non-melanoma skin cancer in the United States.
With about 13 million white non-Hispanic U.S. residents having been treated for at least one non-melanoma skin cancer at the beginning of 2007, that means non-melanoma skin cancers have struck five times as many people as breast or prostate cancer. More people have had non-melanoma skin cancer than all other cancers combined over the last 31 years, according to the study.
Most of those who had a non-melanoma skin cancer had more than one, with the average being 1.6, he noted.
"This is only going to get worse," said Dr. Suephy Chen, an associate professor of dermatology at Emory University School of Medicine in Atlanta. "Our population is aging. Those people who grew up in the 1970s and 1980s when there was not a big sun-protection message out there are now coming into their 50s and 60s and are starting to develop skin cancers."
While non-melanoma skin cancers are the most common, melanoma is a serious worry. Though melanoma accounts for less than 5 percent of all skin cancers, it was expected to lead to an estimated 8,650 deaths in 2009, according to the American Cancer Society.
In a third paper in the same journal, researchers from the U.S. National Cancer Institute found survivors of one melanoma are about nine times as likely as the general population to develop a second melanoma.
Of nearly 90,000 patients who survived at least two months after an initial melanoma diagnosis between 1973 and 2006, about 12 percent developed one or more other primary cancers. One-fourth of those were additional melanomas, according to the study. Women with head and neck melanoma and patients younger than 30 had even higher increased risks of developing another melanoma.
As incidence has risen, so has the cost of treating melanoma. In adults 65 and older, melanoma treatment costs about $249 million annually, or about $28,000 per patient lifetime, according to a fourth study in the same journal by Chen and her colleagues at Emory University.