Shepherd L, Ryom L, Law M, Petoumenos K, Hatleberg CI, d‘Arminio Monforte A, Sabin C, Bower M, Bonnet , Reiss P, de Wit S, Pradier C, Weber R, El-Sadr W, Lundgren J, Mocroft A1; D:A:D Study group. Clin Infect Dis. 2018 Jun 14. doi: 10.1093/cid/ciy508.
Cancers are a major source of morbidity and mortality for HIV-positive persons on combination antiretroviral therapy, while the clinical benefits of smoking cessation are not well established.
Participants were followed from 1 January 2004 until first cancer diagnosis, death, or 1 February 2016. Smoking status was defined as ex (<1,1-2,2-3,3-5,>5 years since stopping), current, and never smokers. Outcomes considered were any cancer, lung cancer, other smoking-related excluding lung and smoking-unrelated cancers. Adjusted incidence rate ratios (aIRR) were calculated using Poisson regression, adjusting for demographic and clinical factors.
35442 persons from the D:A:D study contributed 309803 person years of follow-up. At baseline, 49% of people were current smokers, 21% were ex-smokers, 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%CI: 1.37, 2.02) and not significantly different from never smokers 1-2 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) excluding lung was elevated in the first year after cessation (aIRR: 2.06 95%CI: 1.42, 2.99) and declined to a level similar to non-smokers thereafter. Incidence of smoking-unrelated cancers (N=1290) was unrelated to smoking status.
Lung cancer incidence remained elevated for more than 5 years after smoking cessation. Deterring uptake of smoking and smoking cessation efforts should be a priority to reduce the future risk of cancer.