Lung cancer in the Swiss HIV Cohort Study: Role of smoking, immunodeficiency and pulmonary infection

Background: Immunodeficiency and AIDS-related pulmonary infections have been suggested as independent causes of lung cancer among HIV-infected persons, in addition to smoking.Methods: A total of 68 lung cancers were identified in the Swiss HIV Cohort Study (SHCS) or through linkage with Swiss Cancer Registries (1985-2010), and were individually matched to 337 controls by centre, gender, HIV-transmission category, age and calendar period. Odds ratios (ORs) were estimated by conditional logistic regression. Results: Overall, 96.2% of lung cancers and 72.9% of controls were ever smokers, confirming the high prevalence of smoking and its strong association with lung cancer (OR for current vs never = 14.4, 95% confidence interval (95% CI): 3.36-62.1). No significant associations were observed between CD4+ cell count and lung cancer, neither when measured within 1 year (OR for <200 vs ≥500 = 1.21, 95% CI: 0.49-2.96) nor further back in time, before lung cancer diagnosis. Combined antiretroviral therapy was not significantly associated with lung cancer (OR for ever vs never = 0.67, 95% CI: 0.29-1.52), and nor was a history of AIDS with (OR = 0.49, 95% CI: 0.19-1.28) or without (OR = 0.53, 95% CI: 0.24-1.18) pulmonary involvement. Conclusion: Lung cancer in the SHCS does not seem to be clearly associated with immunodeficiency or AIDS-related pulmonary disease, but seems to be attributable to heavy smoking. © 2012 Cancer Research UK.