Lung cancer 2.5 times more likely in HIV + patients, regardless of smoking

Patients infected with HIV are 2.5 times more likely than HIV-negative to develop lung cancer, regardless of tobacco, according to a U.S. study published in the "Journal of Clinical Oncology" (JCO).

According to the French mortality survey conducted on 964 HIV + people died, lung cancer, considered non-AIDS defining, is, with 19% of deaths, the second cause of death after non-Hodgkin's lymphoma in these patients.

Eric Engels of Johns Hopkins in Baltimore (Maryland) Hospital, and colleagues conducted a study of 5,238 HIV followed between 1989 and 2003.

Among them, 33 patients, including 32 smokers and ex-smokers had lung cancer.

The incidence of 170 cases per 100,000 person-years occurred 6.9 times higher than that found in the general U.S. population and 4.7 times greater than that observed in Detroit (Michigan), the city in which the proportion of smoking is more important than average, chosen as a reference by the authors.

Despite the high proportion of smokers in the HIV population (69%, against 30% of the population of Detroit), smoking does not seem to be the only factor associated with lung cancer. Multivariate analysis has shown that HIV-infected patients experiencing 2.5 times more likely to develop, regardless of smoking.

According to the researchers, "it is difficult to conclude that tobacco is the sole responsibility of the excess risk observed in our cohort."

This effect is illustrated by their high frequency (48%) of adenocarcinomas of these cancers. However, "the association between smoking and lung adenocarcinoma is lower than that found with other histological types of cancers", they said. In addition, small cell carcinomas, "as they are strongly related to tobacco consumption" were present in only two of 33 patients (6%).

Among other assumptions, the researchers suggest that the effects of the virus may interact with those of tobacco, particularly through the production of inflammatory proteins (such as alpha and interleukin-1 TNF), which could amplify the effect of carcinogenic molecules in cigarette smoke.

The authors also noted an increase in the number of cases since the early 80s, which they attributed to the increase in life expectancy since the advent of highly active antiretroviral therapy (HAART). Patients aged 40-49 years prove indeed 5.6 times greater risk of developing lung cancer than those who had less than 40 years.

"As people with HIV are now living longer, cancer certainly occupy an important place among the causes of morbidity and mortality," the researchers warned.

According to a study in the Aquitaine cohort, 50.5% of HIV-positive would be regular smokers, against 30.4% in the general population according to a survey conducted by the National Institute for Prevention and Health Education (INPE) .