Study links skin, other cancers

Non-melanoma could indicate risk of other types

The most common form of skin cancer may be an indicator for risk of other cancers that do not involve the skin.

People with non-melanoma skin cancer have nearly two times the risk of developing other types of cancer, according to a study published Tuesday in the Journal of the National Cancer Institute.

Senior author and principal investigator Anthony Alberg is associate director for cancer prevention and control at the Medical University of South Carolina's Hollings Cancer Center.

Alberg's team compared the risk of cancer in 769 people who had been diagnosed with non-melanoma skin cancer and 18,405 people with no history of disease over the course of a 16-year period.

Non-melanoma skin cancer is a benign form of cancer that is rarely fatal, Alberg said.

After adjusting for a number of variables — including age, sex, body mass, smoking status, education level, skin type and sunburn history —

researchers found that people with a history of non-melanoma skin cancer had a two-fold increase in the risk of subsequent cancers, compared to people with no skin cancer history.

The strongest association between history of skin cancer and later cancers was seen in the youngest participants.

Those between 25 years old and 44 years old at the first onset of non-melanoma skin cancer had 2.6 times the risk of someone with no history. Those from 45 to 59 saw their risk increase 2.2 times, and those 60 and older were at 1.9 times the risk.

The greater risk among younger participants suggests an underlying genetic explanation, Alberg said. He pointed to two possible mechanisms that may be responsible for the increased risk, although neither have been rigorously tested and proven.

One explanation could be a person's inability to repair DNA damage.

"Cancer is a disease of damaged DNA and uncontrolled cell reproduction," Alberg said. When it comes to skin cancer, sun exposure damages the skin's DNA, which then begins to rapidly reproduce. Some people's DNA may have a weaker ability to repair itself, he said.

A second mechanism that may link skin cancer and other cancers is a depressed immune system, which could lead to a greater inflammation response, Alberg said.

Using skin cancer as an example, the degree of sunburn a person suffers would indicate their inflammatory reaction.

"The greater the degree of inflammation response could lead to increased risk of cancer," he said.

Down the road, research such as this study could lead to a genetic profile of an underlying explanation for cancer, Alberg said.

"More work will need to be done to tell how to use this information," he said.

Reach Jill Coley at 937-5719 or jcoley@postandcourier.com.