Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002)

Our plain-English summary of Low-dose computed tomography screening for lung cancer and pleural mesothelioma in an asbestos-exposed population: baseline results of a prospective, nonrandomized feasibility trial--an Alpe-adria Thoracic Oncology Multidisciplinary Group Study (ATOM 002), by G. Fasola, O. Belvedere, M. Aita, et al (The Oncologist, 2007).

The study

• Authors: G. Fasola, O. Belvedere, M. Aita, T. Zanin, A. Follador, P. Cassetti, S. Meduri, V. De Pangher, G. Pignata, V. Rosolen, F. Barbone, F. Grossi
• Journal: The Oncologist
• Published: 2007;12(10):1215-24
• Cited by: 66 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To evaluate the feasibility of using low-dose computed tomography (LDCT) for the early diagnosis of lung cancer and malignant pleural mesothelioma in an asbestos-exposed population.

Methods: Between February 2002 and October 2003, 1,045 volunteers already enrolled in a surveillance program for asbestos-exposed workers and former workers were recruited. The main eligibility criteria were: written informed consent, definite exposure to asbestos, age 40-75, no prior cancer or severe concomitant conditions, no chest CT scan in the past 2 years. A smoking history was not required. After a structured interview, chest X-ray (CXR) and LDCT were performed. Participants with negative examinations were assigned to annual LDCT. Participants with positive findings received high-resolution CT and additional diagnostic workup as appropriate.

Results: Baseline characteristics of the screened population were: median asbestos exposure time, 30 years; median age, 58; median pack-years in smokers/former smokers, 18.5. Thirty-four percent had never smoked. On LDCT, 834 noncalcified nodules were identified in 44% of participants, versus 43 nodules in 4% on CXR. Pleural abnormalities were observed in 44% and 70% of participants by CXR and LDCT, respectively. Overall, LDCT identified nine cases of non-small cell lung cancer-eight stage I, one stage IIA-and one thymic carcinoid, corresponding to 1% of the enrolled population. All cases were radically treated. None had been detected by CXR. No pleural mesothelioma was diagnosed. There were 11 false-positive results.

Conclusions: Our findings first suggest that LDCT may be at least as useful in asbestos workers as in heavy smokers for the early diagnosis of lung cancer; this benefit is evident even in a poor-risk population, with low rates of smoking prevalence and a previous history of radiological surveillance. The role of spiral tomography in screening for pleural mesothelioma remains uncertain.

In plain English

This prospective, nonrandomized feasibility trial in Italy tested low-dose CT scans (LDCT) for early detection of lung cancer and pleural mesothelioma in asbestos-exposed people. Between February 2002 and October 2003, 1,045 asbestos-exposed workers and former workers from a surveillance program in Monfalcone were enrolled. Of these, 97% were men, the median age was 58, 34% had never smoked, and the median asbestos exposure was 30 years. The article does not name fiber types. Each person had a chest X-ray and an LDCT. LDCT found 834 noncalcified lung nodules in 44% of participants, against 43 nodules in 4% on X-ray. It found pleural abnormalities in 70% of participants, against 44% on X-ray. LDCT identified 10 thoracic malignancies (0.96% of participants): nine lung cancers and one thymic carcinoid. All but one were stage I, and none had been seen on the X-ray. No pleural mesothelioma was found. Eleven lesions that went to invasive procedures proved benign. The authors concluded that LDCT may be at least as useful in asbestos workers as in heavy smokers for early lung cancer diagnosis. They considered its role for mesothelioma uncertain and noted the study was too small to test it.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Prospective, nonrandomized feasibility trial; baseline (prevalence) screening results only
• Who was studied: 1,045 asbestos-exposed workers and former workers, aged 40 to 75, enrolled February 2002 to October 2003, drawn from a surveillance program at the Unit of Occupational Health in Monfalcone, northeastern Italy; 1,015 (97%) men; median age 58; 360 (34%) never smokers
• Exposure: Definite occupational asbestos exposure (an eligibility requirement); median duration 30 years (25th to 75th percentile, 26 to 34). Fiber types and specific products are not reported. Smokers and former smokers had a median of 18.5 pack-years.
• Main results:
  • LDCT detected 834 noncalcified nodules in 460 participants (44%); chest X-ray detected 43 nodules in 4% of participants
  • Pleural abnormalities were seen in 44% of participants by chest X-ray (477 abnormalities) and in 70% by LDCT (880 abnormalities); no pleural effusion was found by either method
  • 517 participants (recall rate 49.5%) were sent for high-resolution CT after the baseline scan
  • LDCT identified 10 thoracic malignancies (0.96% of enrolled participants, 1.9% of recalls): nine lung cancers and one thymic carcinoid
  • All malignant cases except one non-small cell lung cancer were stage I; the remaining case was stage IIA
  • None of the malignancies had been identified by the initial chest X-ray
  • No case of malignant pleural mesothelioma was found
  • Invasive diagnostic procedures found 11 benign lesions (2.1% of recalls); none of the participants suffered complications from the diagnostic procedures
  • Because the number of cancers was small, no association could be found between the 10 screen-detected malignancies and age, smoking, duration of asbestos exposure, or time since first exposure
  • Noncalcified nodules on LDCT were not associated with age or asbestos exposure. Smoking at least 25 pack-years was associated with nodules (prevalence odds ratio 1.49, 95% CI 1.06 to 2.09, compared with never-smokers).
  • Pleural abnormalities were associated with age, smoking, and time since first asbestos exposure, but not with duration of exposure
• The authors' conclusion: The authors concluded that their findings suggest LDCT may be at least as useful in asbestos workers as in heavy smokers for the early diagnosis of lung cancer, even in a population with low smoking rates and prior radiological surveillance. They stated that the role of spiral CT in screening for pleural mesothelioma remains uncertain.
• Limitations the authors state:
  • The study was too small to evaluate mesothelioma screening: the authors estimated a minimum sample of about 4,200 subjects, and less than one case was expected at baseline
  • Participants were a highly selected group already in a surveillance program, and more than one third had a chest X-ray before enrolment
  • The small number of cancers and the similar asbestos exposure across participants prevented finding associations with risk factors
  • 52% of invasive procedures were done for benign conditions, well above the 25% reported in other studies; the authors estimated a less stringent nodule algorithm would have cut unnecessary invasive procedures by 30%
  • Whether detecting early-stage disease with LDCT lowers the risk of death from lung cancer is not yet established

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Medical terms in this study, explained in our Lexicon: Low-Dose CT Screening, Lung Cancer, Pleural Mesothelioma, Informed Consent, CT Scan, Chest X-Ray, High-Resolution CT (HRCT), Asbestos Exposure.

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• Diagnostic Performance of Ultra-Low-Dose Computed Tomography for Detecting Asbestos-Related Pleuropulmonary Diseases: Prospective Study in a Screening Setting — M. Schaal, F. Severac, et al. (2016)
• Pleural plaques in lung cancer screening by low-dose computed tomography: prevalence, association with lung cancer and mortality — M. Silva, N. Sverzellati, et al. (2017)
• Low-dose chest computed tomography screening of subjects exposed to asbestos — K. Kato, K. Gemba, et al. (2018)
• Ultra-low-dose chest computer tomography screening of an asbestos-exposed population in Western Australia — F.J. Brims, C.P. Murray, et al. (2015)
• Comment on: "Low-dose computed tomography screening for lung cancer in people with workplace exposure to asbestos" — F. Barbone, F. Barbiero, et al. (2019)

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