AIDS-related lung disease is a major factor in the increased risk of lung cancer seen in people with HIV, the United States AIDS. The study compared rates of lung cancer incidence and survival time between HIV-positive patients and HIV-negative individuals.
"We found that HIV infection alone was not an independent risk factor for lung cancer, but the amount of cigarette smoking over time and AIDS, plus previous pneumonias among HIV-infected adults were the major contributors to the development of lung cancer, "the authors commented.
The incidence of AIDS-related cancers (especially Kaposi's sarcoma and non-Hodgkin's lymphoma) has declined sharply since the introduction of effective antiretroviral therapy (ART). However, several studies have reported an increase in the incidence of lung cancer among people with HIV since the advent of ART. It is unclear whether this increase is simply due to the high rates of smoking seen in people with HIV. There is some evidence that the immune suppression associated with HIV infection and lung damage caused by AIDS-related infection such as PCP pneumonia and recurrent bacterial pneumonia may also be important risk factors for lung cancer.
Faced with such uncertainty, researchers designed a study to determine the incidence of risk factors and survival time for lung cancer among individuals recruited in two longitudinal cohort studies of HIV infection involving women (women HIV Interdepartmental Study [ WIHS]) (n = 2549), other men (Multicenter AIDS Cohort Study [MACS]) (n = 4274)). Both cohorts include an HIV-negative comparison population in at-risk individuals.
Patients were followed up until September of 2012. A total 60 incident of lung cancer (46 in people with HIV, 14 in HIV-negative participants) were recorded among cohort participants. The mean age at diagnosis of lung cancer was 52 years among women with HIV and 51 years among HIV-negative women. For men, the mean age of the diagnosis was 50 years for those with HIV and 54 years for HIV-negative patients. They were all smokers.
Overall, lung cancer incidence was significantly higher among women (IRR = 151,8 by 100.000) than men (IRR = 50,7 by 100.000) (p <0,001). Incidence was also higher among HIV-positive patients (IRR = 119 for 100.000) compared to HIV-negative individuals (IRR = 45 for 100.000) (p = 0,001).
All cases of lung cancer occurred in smokers. Thirty-one 60 cases occurred in people who had accumulated at least thirty years of prior history of smoking. (One pack year is equivalent to smoking 20 cigarettes per day for one year). Pack of ten or more years of smoking was significantly associated with the incidence of lung cancer in a multivariate analysis.
HIV infection was not associated with a significantly increased risk of lung cancer when the two cohorts were analyzed separately. It was only when the two cohorts were combined that HIV became significantly associated with the risk of lung cancer (IRR = 2,64; 95% IC, 1.43-5.21).
After controlling for potential confounders, combined cohort analysis showed that factors independently associated with lung cancer were age, lower education, smoking intensity, and a prior diagnosis of AIDS-related pneumonia.
"We found that about two-thirds of the effect of HIV infection was explained by a prior diagnosis of pneumonia," comments the authors. "Inflammatory lung disease and infections were shown as a performance factor in a role in the development of lung cancer in the general population, and this was also observed among HIV-infected individuals, particularly in association with recurrent pneumonia."
Of the 31cancer's lungs among women diagnosed with HIV, 20 had an earlier AIDS diagnosis, 14 of which involved AIDS-related pneumonia. Of the 15 lung cancer cases among men with HIV, six individuals were involved with the previous AIDS diagnosis, of which three involved pneumonia.
Survival data were available for 56 patients and during follow-up 45 of these individuals died. The average survival time for women was 9,5 months, whereas men survived for an average of six months. Analysis of all 56 patients showed that the only factor associated with longer survival was diagnosis after 2001. A history of injecting drug use was associated with decreased survival.
The researchers, after the restricted analysis for the 42 patients with lung cancer with HIV. The only factor related to HIV independently associated with lung cancer survival was an index of the CD4 count below 200 cells / mm3 (HR = 2,55; 95% IC, 1,09 5,0.95).
"Our data suggest that lung damage and inflammation associated with HIV infection may be an increased risk of lung cancer, the researchers conclude. But they also noted, "Encouraging and helping young HIV-infected smokers to quit and sustain cessation of smoking is imperative to reduce the burden of lung cancer in this population."
Posted in: 22 December 2015 Translated by Cláudio Souza from the original in Previous AIDS-related pulmonary disease associated with lung cancer risk for people with HIV Review Mara Macedo
Hessol NA et al. Incidence of lung cancer and survival among HIV-infected and uninfected patients between men and women. The AIDS 29: 1183-93, 2015.