HIV AND CANCER RISK

HIV-infected men are at twice the risk for non-AIDS defining cancers as the general population, but highly active antiretroviral therapy has a protective benefit, according to a new study.

Little is known about how HIV infection affects the risk for non-AIDS defining cancers that don't have an infectious component. "HIV patients are living longer, and they live with chronic diseases that can compromise the immune system. People with impaired immunologic status are at increased risk for lung cancer," Laura Albini, PhD, professor of infectious diseases at the University of Brescia, Italy, told Medscape Medical News.

She presented the study results here at the 23rd European Congress of Clinical Microbiology and Infectious Diseases.

Dr. Albini and her team conducted a retrospective analysis of 5090 HIV-infected patients registered in the Local Health Authority of Brescia in Northern Italy. The researchers linked their own clinical database to the Local Health Authority general database and the Local Health Authority population-based cancer registry to diagnose nonvirus-related non-AIDS defining cancers.

They used Poisson regression to compare the risk for cancer in people infected with HIV and those in the general population living in the same geographic region.

There were 138 cancers diagnosed in 131 patients over the course of the study (42.6 per 10,000 person-years; median age at diagnosis, 49 years). The most common cancers were nonmelanoma skin (29.7%), lung (16.7%), and breast (7.3%).

More Lung Cancer

Males were at higher risk for cancer (standardized incidence ratio [SIR], 1.86; 95% confidence interval [CI], 1.55 - 2.26) than people in the general population. They also had an increased risk for lung cancer (SIR, 3.59; 95% CI, 2.36 - 5.45) and testis cancer (SIR, 3.11; 95% CI, 1.48 - 6.52).

There were no differences in prostate and breast cancers in HIV-positive men (SIR, 1.10; 95% CI, 0.53 - 2.32) and women (SIR, 0.91; 95% CI, 0.47 - 1.74).

Predictors of nonvirus-related non-AIDS defining cancers included older age (incidence rate ratio [IRR], 1.10; 95% CI, 1.08 - 1.12 for each additional year) and a shorter duration or lack of exposure to highly active antiretroviral therapy (IRR, 2.31; 95% CI, 1.38 - 3.89; P = .002). Severe immunodeficiency (CD4+ count below 50 cells/mm³) was associated with malignancies, but only in the univariate model (IRR, 1.40; 95% CI, 0.99 - 1.98; P = .057).

The increased risk for lung cancer is likely due, in part, to the fact that smoking is a common habit, but immunodeficiency also likely plays a role, according to Dr. Albini.

The results of this study are similar to those from other studies of cancer incidence in HIV-infected individuals, "although there are some differences. Other studies have shown increases in breast cancer, but this one does not," session moderator José Miró, MD, PhD, professor of medicine at the University of Barcelona in Spain, told Medscape Medical News.

The results underscore the importance of lung cancer screening in HIV patients, Dr. Miró added. "Lung cancer is really epidemic in the HIV population. Physicians should use appropriate diagnostic tools if there are any symptoms suggesting lung cancer."