U.S. researchers said that people who have a history of non melanoma skin cancer have double the risk of developing other forms of cancers and the risk is more pronounced in younger people. Lead researcher Anthony Alberg, from the Medical University of South Carolina in Charleston said, "It seems like non-melanoma skin cancer, even though it is a non-fatal disease, may be a warning sign for increased risk of other, more serious cancers. That's not just cancer related to melanoma or other skin cancers."

According to the American Cancer Society, every year in the United States, about 1 million people are diagnosed with non melanoma skin cancers which include basal cell carcinoma and squamous cell carcinoma. Developing these tumors increases the risk of developing melanoma which is the more serious form of skin cancer. Researchers are beginning to explore the link between skin cancer and cancers on other body parts.

The study appears in the Journal of the National Cancer Institute and indicates that a history of the non melanoma tumors doubles the odds for cancer elsewhere. "People with a personal history of non-melanoma skin cancer were two times more likely to develop a subsequent cancer compared to people without a personal history of non-melanoma skin cancer," Alberg said. This doubled risk remained even after factors like age, obesity, history of smoking, level of education, skin type and sun exposure were taken into consideration. People who developed skin cancer between the ages of 25-44 had a 2.6 times higher risk of developing another cancer said the researchers.
"The results were pretty clear in showing the earlier the age of developing non-melanoma skin cancer, the higher the increased risk for subsequent malignancies," he said.

The increased risk was also seen for lung cancer, colon cancer and breast cancer. "For prostate cancer, the trend was in the direction of increased risk, but the association was weaker and not statistically significant," said Alberg.

The increased risk could be due to a weakened ability to repair DNA damage to cells felt Alberg. "People who have suboptimal ability to repair DNA damage that the sun can cause are far more likely to get non melanoma skin cancer. We are hypothesizing that that might also be the link to why there is a greater increased cancer risk in general. If they are less adept at that, their risk for skin cancer increases," Alberg said.

Dr. Robin Ashinoff, a dermatologist at New York University Medical Center, New York City, agreed.  "It is not unreasonable to suppose that patients with non melanoma skin cancers, especially if diagnosed when the patient is young, puts that person in a higher risk category of systemic cancers," Ashinoff said.  "In addition, these patients are followed closely for further skin cancers, and therefore may have an increased diagnosis of other cancers, because they are plugged into the medical system," she added.

"Our skin cancer patients should know that they may be at increased for a wide variety of cancers like breast, lung and colon, and should not ignore early signs and symptoms if they occur," Ashinoff advised.

Dr. Martin Weinstock, chair of the skin cancer advisory committee at the American Cancer Society, said "People who have had skin cancers should make sure they are up-to-date on all their screening tests. They should be up-to-date on their colonoscopies, fecal occult blood and mammograms and Pap smears," he added. In addition, people need to protect themselves from UV exposure, so they don't develop skin cancer in the first place, Weinstock said.

Alberg said though more studies are needed to study individual risks, people who have had non-melanoma cancer should mention it to their doctor. "It seems to be a more important part of a personal health history than we thought before," he said.