Two rare types of skin cancer occur more commonly in people with an AIDS diagnosis than in their HIV-negative peers—while melanoma does not—according to a study published in the January 28 issue of AIDS and reported by aidsmap.

Several types of cancers are more common in people with AIDS (PWAs) and other people with compromised immune systems. In PWAs, Kaposi’s sarcoma and non-Hodgkin’s lymphoma are both AIDS-defining illnesses. Such cancers, along with anal cancer and certain types of skin cancers, occur at higher rates in people with compromised immune systems.

To determine whether PWAs are at increased risk from skin cancer, Emilie Lanoy, MD, from the National Cancer Institute in Rockville, Maryland, and her colleagues examined the medical records of nearly 500,000 PWAs in the United States. Most of the patients were men, and roughly 40 percent were of non-Hispanic white race—in whom skin cancers are most likely to occur. These patients were compared with HIV-negative patients who were similar in regard to age and geographic location.

Just over 300 PWAs developed some form of skin cancer between 1980 and 2004. Lanoy and her colleagues found that although the risk of melanoma was 30 percent higher in PWAs than in HIV-negative patients, the increased risk was not statistically significant. They suggest that the increased melanoma risk seen in PWAs was likely due to greater exposure to the sun and tanning beds.

Two other types of skin cancer, however, were significantly more likely in PWAs compared with HIV-negative patients. PWAs were 11 times more likely to develop Merkel cell carcinoma and more than four times as likely to develop appendageal carcinoma. However, even among PWAs, these cancers are still considered rare.

Lanoy and her colleagues suggest that these cancers may be occurring due to HIV-related immune system damage, and they are encouraging greater awareness and screening for skin cancers in people with AIDS.