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.

Facts About Skin Cancer:

According to the latest statistics available from the National Cancer Institute (NCI) and the Centers for Disease Control and Prevention (CDC):

• Skin cancer is a malignant tumor that grows in the skin cells and accounts for 50 percent of all cancers.

• In the US alone, more than 1 million Americans will be diagnosed in 2008 with nonmelanoma skin cancer, and 62,480 will be diagnosed with melanoma, according to the American Cancer Society (ACS).

• Although exposure to the sun's ultraviolet (UV) rays is said to be the most important factor in the cause of skin cancers, about 70 percent of American adults do not use sun-protection measures.

• Most skin cancers appear in older people, but skin damage from the sun begins at an early age. Therefore, protection should start in childhood to prevent skin cancer later in life.

In addition, consider the following statistics from the ACS and the American Academy of Dermatology:

• Basal cell carcinoma is the most common form of cancer worldwide.

• Non-epithelial skin cancers (such as basal cell and squamous cell) have an overall 5-year survival rate around 88 percent.

• Melanoma incidence rates are 10 times higher for Caucasians than for African-Americans. People with dark-pigmented skin can develop melanoma, particularly on the palms of the hands, on the soles of the feet, under the nails, and inside the mouth.

Forty to 50 percent of Americans who live to the age of 65 will have skin cancer at least once. The most common types of skin cancer in the US are basal cell and squamous cell carcinomas. These are referred to as nonmelanoma skin cancers and are generally the result of sun exposure.

Approximately one in 59 people will develop melanoma during their lifetime. Malignant melanoma is a cancer that begins in the melanocytes, the pigment-producing cells in the skin.

The majority of melanoma cases (90 percent) are due to environmental factors such as ultraviolet radiation (sun exposure). However, about 5 percent to 10 percent of cases occur in people with a family history of melanoma. In some of these families, the risk to develop melanoma will be inherited in an autosomal dominant fashion. In other words, parents with a mutation have a 50/50 chance to pass on the susceptibility to each of their children regardless of gender.

Always consult your physician for more information.