In a study published in the November issue of The Oncologist, Italian researchers reported that CT screening of persons exposed to asbestos is useful for the detection of early lung cancer. The study, which took place between February 2002 and October 2003, evaluated the feasibility of using low-dose computed tomography (CT) for the early diagnosis of lung cancer and malignant pleural mesothelioma in an asbestos-exposed population. Study participants consisted of 1,045 volunteers already enrolled in a surveillance program for asbestos-exposed workers and former workers, age 40-75, with no prior cancer and no chest CT in the prior two years. The median asbestos exposure time was 30 years, median age 58 years old. Sixty-six percent of participants were smokers with a median of 18.5 pack years; thirty-four percent had never smoked. Participants were given chest x-rays and low-dose CT scans.

The results of the CT scans were compared to routine chest x-rays: 834 non-calcified nodules were detected in 44% of participants on initial CT compared to 43 nodules in 4% of participants by chest x-ray; 9 cases of lung cancer were detected by CT and none by chest x-ray; 8 lung cancers were Stage I and one was Stage IIA, and all were treated with surgery; one person had a thymic carcinoid detected by CT. There were 11 false positive results. No cases of mesothelioma were detected in the study. Based on the study, the researchers concluded that low-dose CT may be at least useful in asbestos workers as in heavy smokers for the early diagnosis of lung cancer, even in high-risk populations with low rates of smoking prevalence. The role of spiral tomography in screening for pleural mesothelioma still remains uncertain.