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Pulmonary nodules common in 9/11 responders

More than half of World Trade Center responders with available CT scans had evidence of pulmonary nodules, a recent study shows.

Researchers examined CT imaging data from 1,617 World Trade Center responders taken between 2003 and 2012 from the WTC Chest CT Imaging Archive and the WTC General Responder Cohort Data Center. The study’s primary outcome was the presence of noncalcified nodules, with radiologists evaluating nodule location, consistency, size at largest diameter and presence of calcification. Severity of nodules were classified according to the Lung CT Screening Reporting and Data System (Lung-RADS) criteria.

Arrival at the World Trade Center within 48 hours of the 9/11 attack and World Trade Center exposure duration with a cutoff of 60 days were used as measures for World Trade Center exposure. Multivariable analysis included adjustment for sex, race, age at time of CT scan, educational attainment, income, smoking intensity and status at baseline screening and pre-9/11 occupational exposures, with pleural thickening used as a measure of pre-9/11 respiratory asbestos exposure.

Of the 1,617 participants, 60% had at least one pulmonary nodule, with 52% showing at least one noncalcified solid nodule. Additionally, 55% of all participants had a nodule severity of Lung-RADS 2 and 5% had a nodule severity of Lung-RADS 3 or 4.

Participants with nodule severity of Lung-RADS 3 or 4 also had a higher likelihood of having multiple nodules compared with participants with Lung-RADS 1 or 2 (P < .001).

Participants with more severe nodules were more likely to be older and current smokers, with a trend toward greater pack-year smoking between former or current smokers with Lung-RADS 3 or 4 compared with participants with Lung-RADS 1 or 2. In the unadjusted ordinal regression analysis, pack-years of smoking, age, former smoking history and a concurrent CT finding of pleural thickening were found to be significantly associated with higher Lung-RADS nodule severity. In multivariable analyses, pleural thickening, but not World Trade Center-related exposures, was significantly associated with increasing severity of Lung-RADS findings.

Additionally, there were no differences in National Lung Screening Trial (NLST) nodule positivity between World Trade Center responders who met NLST criteria at earliest CT scan and matched NLST first-round participants.

The researchers noted that the prevalence of pulmonary nodules in this cohort of World Trade Center responders is on par with those seen in lung cancer screening cohorts.

“Aside from pleural thickening, consistent with pre-World Trade Center asbestos exposure, neither World Trade Center nor pre-World Trade Center occupational exposure variables were associated with nodular lung disease. Our findings, if replicated, could be supportive of the recommendation to ‘relax’ lung cancer screening eligibility criteria in consideration of occupational and environmental exposures, which may be highly relevant in the World Trade Center and other occupationally exposed populations. With low-dose CT-based lung cancer screening for heavy smokers now a standard of care in the United States, and a sizeable proportion of smokers among the World Trade Center responder population, many may be referred for screening as the cohort ages,” the researchers wrote. “Estimating the influence of World Trade Center-related and unrelated occupational exposures on the presence of noncalcified nodules is an additional factor to assess the benefits associated with lung cancer screening in this group.” – by Eamon Dreisbach

Disclosures: Three of the authors report they received funding for the study from CDC and the National Institute for Occupational Safety and Health.