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CESSATION OF CIGARETTE SMOKING AND THE IMPACT ON CANCER INCIDENCE IN THE D:A:D STUDY
Leah Shepherd1, Lene Ryom2, Kathy Petoumenos3, Camilla Ingrid Hatleberg2, Antonella d'Arminio Monforte4, Fabrice Bonnet5, Peter Reiss6, Jens D. Lundgren2, Amanda Mocroft1
1Univ Coll London, London, UK,2CHIP, Copenhagen, Denmark,3Kirby Inst, Sydney, Australia,4Univ of Milan, Milan, Italy,5CHU de Bordeaux, Bordeaux, France,6Stichting HIV Monitoring and Academic Med Cntr, Amsterdam, Netherlands
Cancers are a major source of morbidity and mortality in the cART era. The prevalence of smoking in HIV+ people is 40–70% and the clinical benefits of smoking cessation on cancer risk have not been reported. We aimed to estimate cancer rates after smoking cessation in persons from the D:A:D study.
Persons were followed from the latest of study entry or 1/1/2004 until earliest of first cancer diagnosis, last visit plus 6 months, death, or 1/2/2015. Three outcomes were considered: all cancers combined, lung cancer, and other smoking-related excluding lung cancer (OSRC; see footnote). Smoking status was defined as current and never smokers, those who stopped during follow-up (<1,1-2,2-3,3-5,5> years since stopping) and those who stopped prior to baseline. Adjusted rate ratios (aRR) were calculated using Poisson regression.
39701 persons contributed 315327 person years of follow-up (PYFU) (median: 9 IQR: 6, 11 years per person). At baseline, 41% of people were current smokers, 17% were ex-smokers, 27% never smoked. 2230 developed cancer (IR 7.1/1000 PYFU, 95%CI: 6.8, 7.4), of which 251 were lung cancers (IR 0.8/1000 PYFU, 95%CI: 0.7, 0.9) and 516 were OSRC (IR 1.6/1000 PYFU 95%CI: 1.5, 1.8). Incidence of all cancers combined (Figure) was highest <1 year after quitting compared to those who had never smoked (aRR: 1.62 95%CI: 1.32, 1.99) and was similar to never smokers thereafter. Lung cancer incidence was over 11-fold higher <1 year after quitting (aRR: 11.72 95%CI: 4.81, 28.57) and remained >8-fold higher even after 5 years (aRR: 8.26 95%CI: 2.83, 24.09) with no evidence of decline when compared to non-smokers. OSRC incidence was almost 3-fold higher <1 year after quitting (aRR2.52 95%CI: 1.69, 3.74), but was similar to never smokers thereafter. Smoking duration was associated with the occurrence of all cancers combined (Per year longer aRR: 1.03 95%CI: 1.01,1.04), lung (aRR: 1.07 95%CI: 1.01, 1.12), but not OSRC (aRR: 1.03 95%CI: 0.99, 1.06). No significant interactions between smoking status and age, gender or CD4 were found.
Overall cancer incidence declined to that of non-smokers after one year quitting except for lung cancer incidence, which did not decrease even >5 years after quitting. Smoking cessation efforts should be a priority to reduce the risk of cancer, however, surveillance and screening of lung cancer should not be stopped in patients who stop smoking.