Researchers who followed skin cancer survivors for 16 years have concluded that they are twice as likely as people without skin cancer to develop another form of cancer later on.
The new study, from Johns Hopkins and the Medical University of South Carolina, tracked 769 patients who had non-melanoma skin cancer -- the most common form in the United States -- and 18,405 people who had not had the illness and found that those who had skin cancer were twice as likely to develop another form.
Among the cancers skin cancer survivors would ultimately contract, melanoma was by far the most common, with eight times the risk. The researchers also found that these people experienced an increased risk for lung, colorectal, breast, and prostate cancers.
The news could be enough to give pause to millions of Americans who have battled skin cancer in the past -- among them Republican presidential candidate Sen. John McCain. McCain has weathered six instances of non-melanoma skin cancer, the type studied in the research.
However, the findings of higher cancer rates were most prominent among the youngest skin cancer patients in the study, who were between the ages of 25 and 44, so they are unlikely to have much bearing, if any, on the nation's most famous skin cancer survivor, who turns 72 Friday.
Although the findings are considered preliminary, part of the reason for this, the researchers speculate, is that the findings indicate that people's DNA have different repair abilities, which make some less able to repair damage from environmental irritants and more likely to develop cancer.
But in McCain's case, the origins of his skin cancer are likely from exposure to sunlight in his environment.
"I think if someone -- like John McCain, for example -- has very fair skin, light eyes and a history of living in a place like Arizona, that is a darn good explanation for his skin cancers, and he is healthy otherwise … so the chances of his non-melanoma skin cancers being a marker for other DNA repair problems is slim in my opinion," said Dr. Mark Abdelmalek, a regular contributor to ABC News, who reviewed McCain's health records on behalf of ABC when they were released in May.
But for others, the new research could offer intriguing hints to the origin of their skin cancers -- and perhaps one day an early warning of future risk.
"A personal history of non-melanoma skin cancer may be more a part of personal health history than we thought before," said Anthony Alberg, associate director for cancer prevention and control at the Hollings Cancer Center of MUSC and one of the study's lead authors.
For the study, skin cancer records were taken from a registry in Washington County, Md., and subjects gave demographic information at the beginning of the study, before their health histories were tracked for the next 16 years.
The study appears in the newest issue of the Journal of the National Cancer Institute.
While some are calling the findings promising, Alberg stresses that they probably won't affect the clinic at this time.
"It's too early to know what to do with this information," he said.
While avoiding skin cancer earlier by using sunscreen and avoiding exposure might not necessarily reduce later cancer risks, Alberg noted that, "Taking steps to avoid non-melanoma skin cancer would be wise anyway."