title: Western Australian cigarette smokers have fewer small lung nodules than North Americans on CT screening for lung cancer.
abstract: To determine the prevalence of small lung nodules on low-dose helical computed tomography (CT) in a Western Australian cohort of asymptomatic long-term cigarette smokers and to compare this with a large, similarly derived cohort of North Americans from the Mayo Clinic Lung Cancer Screening Trial. Forty-nine asymptomatic long-term cigarette smokers of minimum age 50 years underwent a low-dose 64-slice helical CT of the lungs. Images were viewed on a soft copy reporting station with thin section axial and coronal images, maximum intensity projection images, and advanced image manipulation tools. The prevalence of all nodules was 39%, significantly lower than the Mayo Clinic cohort prevalence of 51% (P < 0.01, Fisher's exact test), despite the use of more advanced imaging technology and image manipulation designed to increase the sensitivity for nodules. The prevalence of small nodules in asymptomatic long-term cigarette smokers in Western Australia is high, though significantly less than that found in a large study in North America. The authors postulate this is due to the relatively low rates of mycobacterium tuberculosis and soil-derived fungal pulmonary infections in Western Australia, as well as a lower degree of urban air pollution.
authors.affiliation: Department of Interventional and Diagnostic Radiology, Royal Perth Hospital, Perth, Western Australia, Australia. conor.murray@health.wa.gov.au
authors.forename: C P
authors.initials: CP
authors.lastname: Murray
authors.forename: P M
authors.initials: PM
authors.lastname: Wong
authors.forename: J
authors.initials: J
authors.lastname: Louw
authors.forename: G W
authors.initials: GW
authors.lastname: Waterer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009656:North America / Q000453:epidemiology; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012907:Smoking / Q000453:epidemiology*; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed / Q000706:statistics & numerical data*; D014904:Western Australia / Q000453:epidemiology