Women infected with HIV or at risk of becoming infected with HIV, the virus that causes AIDS, appear more likely to develop lung cancer than women in the general population, possibly because they are much more likely to smoke cigarettes, study findings hint.

People with HIV have a much higher risk for many cancers. Still, it is unclear whether HIV infection plays a role in the development of lung cancer, Dr. Alexandra M. Levine, at City of Hope National Medical Center in Duarte, California, and colleagues note in the Journal of Clinical Oncology.

To investigate, they compared lung cancer cases in 2,651 HIV-infected and 898 at-risk but uninfected women, who were 35 years old on average, with lung cancer cases estimated to occur among similarly aged women in the general population.

“We found a substantially increased risk of lung cancer among both HIV-infected and at-risk uninfected women compared with population-based expectations,” the team reports.

Specifically, population estimates suggested that the researchers would find between four and five lung cancer cases. Instead, over five years of follow up, they found 14 lung cancers - 12 in HIV-infected women and two in women at risk for HIV infection.

However, further analysis revealed that only smoking history and duration “were significantly associated with lung cancer” in the women with HIV or at risk for HIV infection.

Approximately two-thirds of women in the HIV group smoked. All of the women that developed lung cancer smoked, and over their lifetime smoked about double the amount of cigarettes as their lung cancer-free peers.

“As such, the development and implementation of smoking cessation programs aimed at HIV-infected persons will be of increasing importance,” the investigators wrote.

There were no lung cancer cases among the women who were lifetime non-smokers.

Several studies, Levine and colleagues note, have shown a significant increase in lung cancer among HIV-infected patients since the introduction of highly active AIDS drugs. Yet, they found no difference in lung cancer development among women infected with HIV before or after the availability of powerful AIDS drugs, suggesting, they say, that lung cancer is not associated with the use of AIDS drugs.

“The precise role of HIV infection, per se, in terms of the development or progression of lung cancer” needs further study, the researchers conclude.

SOURCE: Journal of Clinical Oncology, published online February 22, 2010