Christopher Donatelli

M.D.

University Hospitals Cleveland Medical Center

Fellow, Pulmonary and Critical Care Medicine

NLST (Learn more about this study)

NLST-250

Oct 13, 2016

Outcomes among patients with self-reported occupational exposures in the NLST

The National Lung Screening Trial results demonstrated a reduction in lung-cancer mortality with three rounds of annual CT screening versus annual chest x-ray. A 20% relative reduction in mortality, or absolute reduction in mortality in 3 per 1000 individuals, was shown. This finding highlights the potential impact of lung cancer screening in current or former smokers. However, many questions regarding widespread implementation of lung cancer screening remain. These include the application of lung cancer screening to specific populations of individuals at high risk of developing lung cancer. It is therefore important to better understand the clinical outcomes of CT screening in high-risk patient populations since these groups are more likely to benefit from screening.

Occupational exposure to asbestos and other particles is associated with both benign and malignant pulmonary and pleural diseases. Lung cancer is the most common cancer associated with occupational exposures. Approximately 28% of participants in each arm of the NLST self-reported occupational exposure(s) known to be associated with increased risk for lung cancer. Specifically, about 5% of the participants reported working with asbestos. Lung cancer risk related to asbestos exposure has been shown to be independent of cigarette smoking history; it is greatly increased in those individuals with exposure to cigarette smoke plus asbestos. Previous studies have shown increased detection of nodules and other lung imaging abnormalities on CT scans obtained for lung cancer screening in workers exposed to asbestos. Concerns have been raised about the potential for harm from lung cancer screening, including overdiagnosis, psychological distress, and radiation exposure.

We hypothesize that the cohort of patients in the NLST who reported occupational exposures may have more positive screening results compared to similar patients without the same occupational exposures. This cohort of patients may also have had increased diagnosis of lung cancer and increased utilization of diagnostic tests or procedures during the NLST follow-up period. We would like to examine patient-related outcomes observed in the high-risk subgroup of individuals with occupational exposures who participated in the NLST. We plan to analyze prospectively-collected data from the NLST. Categorical and numerical variables of interest include age, race, smoking history, family history of lung cancer, and other socioeconomic information available in the dataset. The results of prevalence and follow-up screening CT scans would be analyzed to determine the number of tests with positive findings (noncalcified nodules > 4 mm), in addition to other pulmonary parenchymal and pleural abnormalities. Data on lung cancer diagnosis, pathologic diagnosis, staging, and survival would also be collected.

Previous research has demonstrated that computer-aided nodule assessment can effectively risk-stratify lung adenocarcinomas based on CT imaging analysis. We also plan on collaborating with colleagues at Case Western Reserve University to explore the application of radiomics analysis to CT scan data from the NLST as a method of non-invasively risk stratifying lung nodules in this high-risk subgroup of individuals with occupational exposures and smoking history.

1. Examine the demographics of a high-risk subgroup of individuals with occupational exposure(s) and smoking history who participated in the NLST. And compare this group to a similar group of individuals in the NLST without occupational exposures.

2. Examine outcomes of lung cancer screening in a high-risk subgroup of individuals with occupational exposure(s) and smoking history who participated in the NLST. These outcomes would include measures such as rate of positive screening results, incidental findings, other lung parenchyma and pleural imaging findings, additional diagnostic procedures or biopsies, staging and diagnosis, and survival.

3. Explore the application of computer extracted texture and shape feature analysis of nodules on CT scan data from the NLST, including CT scans from participants who reported occupational exposures to asbestos and other particles.