High Frequency of Early Lung Cancer Diagnosis With Chest CT in HIV-Infected Smokers

Background: The National Lung Screening Trial has provided compelling evidence of the efficacy of lung cancer screening using chest low-dose computed tomography (LDCT) to reduce lung cancer mortality, but further studies are needed to evaluate LDCT screening in different populations. We sought to study the feasibility and to identify specificities of early lung cancer diagnosis with LDCT in HIV-infected smokers.

Methods: The ANRS EP48 HIV CHEST study is a French, multicentre, prospective study consisting of a one round, millimetric, chest LDCT of HIV-infected subjects ≥ 40 years with a history of cumulative smoking within the last 3 years ≥ 20 pack-years, a CD4 T-lymphocyte nadir cell count < 350/µl, and a last CD4-T cell count > 100 cells/µl. A significant nodule on baseline CT, inducing CT follow up or immediate diagnostic procedures, was defined by a solid or partly solid nodule ≥ 5 mm or a non solid nodule ≥ 8 mm. Follow up and biopsy procedures were suggested in a workup algorithm, with a systematic follow-up of 2 years. Under the hypothesis of a 2.6 increased risk of lung cancer in HIV-infected smokers versus HIV-uninfected counterparts, we estimated lung cancer prevalence to be 3%. Hence, we aimed to enrol 445 patients, and expected 13 diagnosis of lung cancer [95% Confidence Interval, 7-22].

Results: Between March 2011 and June 2012, 442 subjects were enrolled. Median age was 49.8 years, (interquartile range (IQR) 46.3-53.9), 84% were men, median cumulative smoking was 30 pack-years (IQR 25-40), median last CD4 and nadir CD4 cell counts were 574/µl (IQR 408-765) and 168/µl (IQR 75-256) respectively, and 90% had a plasma HIV RNA < 50 copies/ml. A significant nodule was reported in 94 (21%) subjects on baseline CT. Lung cancer (5 staged IA) was diagnosed in 8 subjects (1.81 %), all but one in subjects aged < 55 years (table). There were no serious adverse events due to diagnostic procedures, and 29 subjects were lost to follow up. Conclusions: Early lung cancer diagnosis and nodule follow up with LDCT are feasible in HIV-infected smokers. Prevalence of lung cancer was within expected range and 5/8 cancers were surgically curable stage IA. The rate of significant nodules on baseline CT was not higher than the ranges published in non HIV-infected screening studies. Lung cancer screening of subjects between the ages of 55-74 years as recommended in the general population may miss substantial numbers of cancers in HIV-infected smokers with a nadir CD4 cell count < 350/µl.

M : Male; F: Female