Nonmelanoma Skin Cancer Linked to Risk for Other Cancers

Aug. 27, 2008 — A new study has found that people with a history of nonmelanoma skin cancer face twice the risk of developing other malignancies.

Researchers reporting in the Journal of the National Cancer Institute say that a history of nonmelanoma lesions doubles the odds for a subsequent cancer. "That's not just cancer related to melanoma or other skin cancers," notes lead researcher Anthony Alberg, Ph.D., from the Medical University of South Carolina.

Every year in the US, about 1 million people are diagnosed with nonmelanoma skin cancers, according to the American Cancer Society (ACS). Developing these tumors is known to increase the risk for melanoma, the most serious form of skin cancer. But the link between skin cancer and cancers at other body sites is just beginning to be explored.

Greater Risk for Lung, Colon, and Breast Cancers
In this study, the increased risk was seen for lung cancer, colon cancer, and breast cancer, Dr. Alberg says. "For prostate cancer, the trend was in the direction of increased risk, but the association was weaker and not statistically significant," he says.

Dr. Alberg believes the increased risk may be due to a weakened ability to repair DNA damage to cells. "People who have suboptimal ability to repair DNA damage that the sun can cause are far more likely to get nonmelanoma skin cancer. We are hypothesizing that that might also be the link to why there is a greater increased cancer risk in general," he says.

For the study, Dr. Alberg's team looked at the risk of developing cancer among 769 people with a history of nonmelanoma skin cancer. The researchers compared these people to 18,405 people with no history of skin cancer.

Over 16 years of follow-up, the researchers found that the incidence of cancers was 293.5 per 10,000 person-years among people with a history of skin cancer, compared to 77.8 per 10,000 person-years among people without a history of the disease.

In addition, the younger a person got a nonmelanoma skin cancer, the higher his or her risk of developing other cancers, says Dr. Alberg.

Repair of DNA Damage a Factor?
Dr. Robin Ashinoff, a dermatologist at New York University Medical Center in New York City, agrees that the inability to repair DNA damage associated with nonmelanoma skin cancer may make developing other cancers more likely.

"It is not unreasonable to suppose that patients with nonmelanoma skin cancers, especially if diagnosed when the patient is young, puts that person in a higher risk category of systemic cancers," Dr. Ashinoff says.

People who develop skin cancers may have inherited a family tendency for other cancers because of inadequate ability to repair DNA, Dr. Ashinoff says. "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 notes.

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

Cancer Screening Important
Dr. Martin Weinstock, chair of the skin cancer advisory committee at the ACS, says awareness and testing are key.

"People who have had skin cancers should make sure they are up-to-date on all their screening tests," Dr. Weinstock says. "They should be up-to-date on their colonoscopies, fecal occult blood, and mammograms and Pap smears," he says.

In addition, people need to protect themselves from UV exposure, so they do not develop skin cancer in the first place, Dr. Weinstock adds.

Always consult your physician for more information.