Visual, quantitative CT emphysema assessments linked to higher odds of lung cancer
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Both visual and quantitative CT assessments of emphysema were associated with greater odds of lung cancer, researchers reported in Radiology.
Moreover, odds of lung cancer increased with emphysema severity.
Researchers performed a systematic review and meta-analysis on the association between emphysema assessed via chest CT and lung cancer. Researchers screened PubMed, Embase and Cochrane databases through July 2021 to identify studies that investigated associations between emphysema and lung cancer. Their search yielded 3,343 studies; 21 studies with 26 subsets evaluating 107,082 patients were included.
Overall, 3,907 patients in the 21 studies had lung cancer. Cohort studies contributed to 1,868 lung cancer cases and case-control studies contributed to 2,039 cases.
The researchers reported that the overall pooled estimate for the association between emphysema and lung cancer was 2.3 (95% CI, 2-2.6) and the pooled OR for every 1% increase in the low attenuation area percentage was 1.02 (95% CI, 1.01-1.02).
In studies that used visual assessment, the pooled OR for lung cancer given emphysema was 2.3 (95% CI, 1.9-2.6). For studies that used quantitative dichotomous assessment, the pooled OR was 2.2 (95% CI, 1.8-2.8), according to the results.
Odds of lung cancer rose with emphysema severity and were higher for visual assessment (OR = 1.9 for trace; OR = 3.7 for mild; OR = 4.5 for moderate to severe) compared with quantitative assessment (OR = 1.9 for trace; OR = 2.2 for mild; OR = 2.5 for moderate to severe), the researchers wrote.
In addition, only centrilobular emphysema, seen in three included studies, was associated with lung cancer (OR = 2.2; 95% CI, 1.5-3.2; P < .001) compared with no emphysema.
“In conclusion, emphysema diagnosed at chest CT was independently associated with a higher odds of developing lung cancer, regardless of whether it was assessed visually or quantitatively. ... To benefit from the potential value of visual and quantitative CT assessments in early emphysema detection and lung cancer screening, research must now establish guidelines for scanning protocols, evaluation and nodule risk stratification,” Xiaofei Yang, MD, from the department of epidemiology at the University Medical Center Groningen at the University of Groningen, the Netherlands, and colleagues wrote.
In an accompanying editorial, Andetta R. Hunsaker, MD, chief of thoracic imaging at Brigham and Women’s Hospital and associate professor of radiology at Harvard Medical School, said the implications of these findings “are valuable for patient care.”
According to Hunsaker, “It may be that lung cancer screening as we know it will need to undergo some modification to include emphysema as one of the category descriptors, which will contribute to the Lung CT Screening Reporting and Data System score and follow-up screening intervals. Adding emphysema as a separate risk category will improve the identification of those at higher risk for lung cancer and put them in the category of early detection. This can help in identifying the optimal frequency of lung cancer screenings in all populations with smoking-related disease. Those with emphysema may need more frequent screening, whereas those without emphysema and a negative initial screening can be imaged at longer intervals in a more cost-effective way.”