Screening for malignant pleural mesothelioma and lung cancer in individuals with a history of asbestos exposure.
OBJECTIVE
We established a screening program for prior asbestos workers using low-dose computed tomography (LDCT).


METHODS
Between March 2005 and October 2007 we performed LDCT (50-60 mA, 120 kV, 1.25 mm) in 516 asbestos-exposed individuals. Parenchymal nodules were followed according to lung cancer screening recommendations, morphology and location of pleural plaques was noted in detail.


RESULTS
We included 507 men and 9 women (median 60.0 years), 395 (76.6%) were smokers. Annual repeat has been performed in 356 participants. We found plaques in 357 subjects (69.2%), commonly calcified (79.6%), flat (86.6%), and symmetric (86.8%), and mostly involving the costal (96.4%) and diaphragmatic (81.8%) pleura. Uncommon plaques were lobulated (13.2%), right-dominant asymmetric (4.5%), or with effusions (0.1%).We found pulmonary nodules in 371 subjects (71.9%), 91 (17.6%) had at least one nodule > or =5 mm; 10 growing nodules were found on annual repeat LDCT. In 41 individuals, plaques were regarded as atypical; three had new pleural/peritoneal abnormalities on annual repeat LDCT. An interim limited computed tomography of the observed abnormality prompted 10 diagnostic biopsies, resulting in a diagnosis of six lung cancers, two pleural mesothelioma and two peritoneal mesothelioma; overall rate of screen-detected malignancies is 2.1%. There were four interval cancers, diagnosed after baseline (n = 1) or after the annual repeat (n = 3): two pleural and one peritoneal mesothelioma, and one mixed squamous/small cell carcinoma.


CONCLUSIONS
Screening prior asbestos workers detects advanced malignant pleural mesothelioma and early as well as late stage lung cancer. We expect to learn more about the appearance of "early mesothelioma" with continued screening.
Department of Medical Imaging, University Health Network, ON, Canada. heidi.roberts@uhn.on.ca
Heidi C
HC
Roberts
Demetris A
DA
Patsios
Narinder S
NS
Paul
Marc
M
DePerrot
Warren
W
Teel
Hamid
H
Bayanati
Frances
F
Shepherd
Michael R
MR
Johnston
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001194:Asbestos / Q000009:adverse effects*; D002273:Carcinogens; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000209:etiology; D008297:Male; D008403:Mass Screening; D008654:Mesothelioma / Q000000981:diagnostic imaging* / Q000209:etiology; D008875:Middle Aged; D009367:Neoplasm Staging; D016273:Occupational Exposure / Q000009:adverse effects*; D010997:Pleural Neoplasms / Q000000981:diagnostic imaging* / Q000209:etiology; D011379:Prognosis; D003074:Solitary Pulmonary Nodule / Q000473:pathology; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D055815:Young Adult
D002273:Carcinogens; D001194:Asbestos