Benign Skin Cancer Linked to Increased Risk for More Serious Cancers

Non-melanoma skin cancer, formally known as basal cell or squamous cell carcinoma, is the most commonly developed skin cancer affecting 1 million people in the United States each year. It is often easily detected and, when treated properly, has a cure rate of 95 percent, according to the American Academy of Dermatology. This type of cancer rarely spreads to other parts of the body, but it can extend below the skin to the bone and cause considerable local damage. Doctors already know that non-melanoma skin cancer places people at high risk for developing additional skin cancers, but new research indicates it may also increase the risk of developing other malignancies in the body.

A team of researchers led by Jiping Chen, M.D., Ph.D., of the National Cancer Institute and Anthony Alberg, Ph.D., MPH, associate director for cancer prevention and control at the Hollings Cancer Center of the Medical University of South Carolina in Charleston looked at the data from a 16-year study involving 19,174 residents in Washington County, Maryland; 769 with non-melanoma skin cancer and 18,405 who were cancer free. After measuring and comparing the cancer risk of the participants, they found that individuals aged 25 to 44 who suffered from non-melanoma skin cancer were 2.6 times more likely to develop other types of cancer later in life, compared to those who never experienced the disease. In addition, the younger a person developed non-melanoma skin cancer, the higher their risk of developing other cancers.

Among the cancers likely to be contracted, melanoma was the most common, with eight times the risk, but there was also an increased risk of developing lung, colorectal and breast cancers. Prostate cancer was also linked but the association was not statistically significant. "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," Dr. Alberg said.

Researchers speculate that part of the reason for the increased risk is that some people have difficulty repairing DNA damage, which make them more susceptible to environmental irritants and more likely to develop cancer. Furthermore, patients who have survived non-melanoma skin cancer are visiting their doctors regularly for follow-ups and are therefore more likely to be diagnosed with other cancers. "A personal history of non-melanoma skin cancer may be more a part of personal health history than we thought before," said Dr. Alberg.

Margaret Karagas, associate director of the Center for Environmental Health Sciences at Dartmouth Medical School, told ABC News that this study could provide a "useful model" for future cancer research, listing radiation and arsenic among the cancer-causing agents that were initially discovered because they caused skin cancers. "It is also important because in many parts of the world it appears to be one of the most rapidly increasing cancers," she said.

Another study led by Jennifer Christian from the VA Medical Center and Brown University found that patients taking blood pressure-lowering drugs called angiotensin-converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARBs) had a 39 percent lower risk of developing basal cell skin cancer and a 33 percent lower risk of developing squamous cell skin cancer. The researchers say it is unclear why these drugs lower the risk of skin cancer.

Non-melanoma skin cancer is commonly caused by excessive exposure to the sun's UV rays. It starts in the top layer of skin and usually appears as a small, shiny bump or module on the skin, mainly on the areas exposed to the sun, such as the head, neck, arms, hands, and face. You can reduce your risk of developing skin cancer by applying a water-resistant sunscreen with an SPF of 15 or higher, one that protects against both UVA and UVB rays, 20 to 30 minutes before going out into the sun, and reapplying it every hour or two. You should also avoid prolonged exposure to the sun's rays, especially between 10 a.m. and 2 p.m., which is the hottest part of the day. And remember that early detection is of the utmost importance, so if you notice any signs of skin cancer, notify your health care provider right away.

Both studies mentioned above were published in the August 26 online version of the Journal of the National Cancer Institute.