Cessation of cigarette smoking and the impact on cancer incidence in human immunodeficiency virus-infected persons: The data collection on adverse events of anti-HIV drugs study

Background. Cancers are a major source of morbidity and mortality for human immunodeficiency virus (HIV)-infected persons, but the clinical benefits of smoking cessation are unknown. Methods. Participants were followed from 1 January 2004 until first cancer diagnosis, death, or 1 February 2016. Smoking status was defined as ex-smoker, current smoker, and never smoker. Adjusted incidence rate ratios (aIRRs) were calculated using Poisson regression, adjusting for demographic and clinical factors. Results. In total 35 442 persons from the Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) study contributed 309 803 person-years of follow-up. At baseline, 49% were current smokers, 21% were ex-smokers, and 30% had never smoked. Incidence of all cancers combined (n = 2183) was highest <1 year after smoking cessation compared to never smokers (aIRR, 1.66 [95% confidence interval {CI}, 1.37-2.02]) and not significantly different from never smokers 1-1.9 years after cessation. Lung cancer incidence (n = 271) was elevated <1 year after cessation (aIRR, 19.08 [95% CI, 8.10-44.95]) and remained 8-fold higher 5 years after smoking cessation (aIRR, 8.69 [95% CI, 3.40-22.18]). Incidence of other smoking-related cancers (n = 622) was elevated in the first year after cessation (aIRR, 2.06 [95% CI, 1.42-2.99]) and declined to a level similar to nonsmokers thereafter. Conclusions. Lung cancer incidence in HIV-infected individuals remained elevated >5 years after smoking cessation. Deterring uptake of smoking and smoking cessation efforts should be prioritised to reduce future cancer risk.