Epidemiology

Most cancer screening guidelines appropriate for people with HIV

Last Updated: 2010-10-04 18:06:10 -0400 (Reuters Health)

By Karla Gale

NEW YORK (Reuters Health) - Most cancer screening guidelines for the general population can be applied to patients with HIV, according to investigators at the National Cancer Institute in Rockville, Maryland.

The incidence of AIDS-defining types of cancer - e.g., Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer - has declined substantially since the introduction of highly active antiretroviral therapy (HAART).

On the other hand, "several prior studies have shown that, on average, people with HIV/AIDS develop cancer 20-30 years earlier than the general population," Dr. Meredith S. Shiels explained. "However, very few older people are infected with HIV. As a result, the average age of AIDS patients who develop cancer is inherently younger, reflecting the younger age distribution of the population."

Lead author Dr. Shiels and her colleagues used data from the U.S. HIV/AIDS Cancer Match Study, which links 15 population-based HIV/AIDS and cancer registries. Their analysis included 212,055 persons with AIDS followed for cancer between 1996 and 2007 (during the HAART era).

For most types of cancer, the median observed ages at diagnosis were roughly 20 years younger in the AIDS group than in the general population, the investigators report in the Annals of Internal Medicine for October 5. However, the proportion of total person-years contributed by persons aged 65 or older was 1.5% among the AIDS group vs 12.5% in the general population.

"We used a method called 'indirect standardization' to adjust for differences in age distribution," Dr. Shiels said in an email to Reuters Health. "This technique allows us to make the general population 'look like' the HIV/AIDS population in terms of age and other factors. As a result, the comparisons in our study were made between equivalent populations. We compared the age at cancer diagnosis for the adjusted general population to the age at cancer diagnosis in the HIV/AIDS population."

Before adjustment, the median observed age at diagnosis of colon cancer was 52 years in people with AIDS and 72 years in the general population. However, the median expected age after adjustment for age distribution in the general population was 52 years.

Ages at diagnosis were also similar for prostate, breast, and liver cancer when comparing observed cases in AIDS patients and expected cases in the general population.

"Our study shows that for most cancers there is no difference in age at diagnosis between people with AIDS and the general population. Thus, our results do not support the practice of cancer screening at earlier ages in HIV-infected individuals for most cancers," Dr. Shiels said.

"However, all individuals should talk with their health care providers about the screening regimen that may be best for them," she concluded, particularly for types of cancer for which risk is particularly high in HIV.

SOURCE: http://link.reuters.com/wat76p

Ann Intern Med 2010;153:452-460.