A reporting system for lung cancer screening with low-dose computed tomography may underemphasize important abnormal findings other than nodules, researchers say, potentially leading to missed malignancies.

The American College of Radiology Lung Imaging Reporting and Data System, or Lung-RADS , was introduced in 2014 to standardize reporting for low-dose CT findings and also to reduce false-positive rates, by applying tighter criteria that was used in the National Lung Screening Trial .

Lung-RADS does not have specific reporting categories for patients with isolated hilar and mediastinal adenopathy or pleural effusion in the absence of lung nodules, even though these can indicate malignancy. It does allow for the inclusion of what is called an “S” code to indicate clinically significant findings other than nodules.

In the March 2017 issue of CHEST, Hiren Mehta, MD , and his colleagues at the University of Florida in Gainesville, report on four cases from their center in which patients with these pathologies had their scans read as Lung-RADS category 1, indicating a less than 1% likelihood of malignancy. No S codes were added to their reports. Subsequent testing in these patients revealed cancers (CHEST. 2017 March;151[3]:525-26).

The four cases were:

Dr. Mehta and colleagues noted in their analysis that Lung-RADS has not been studied prospectively in real practice settings and that the four cases – two of which involved delayed diagnosis – reveal “a significant limitation” of Lung-RADS.

“Based on our experience, we believe that particular caution should be exercised in reporting Lung-RADS 1 category for patients with adenopathy/pleural effusion with no lung nodules, as a majority of the lung cancer screening scans will be ordered by [primary care providers] … [As] with any new system, an ongoing evaluation of the performance of Lung-RADS should be conducted so that the sensitivity and mortality benefit seen in the [National Lung Screening Trial] is not compromised.”

We strongly believe, based on our experience with these 4 cases that the new version of Lung-RADS 2.0 should [account for shortcomings of the current Lung-RADS] and have a separate category for findings that are highly suspicious for malignancy but do not have an accompanying lung nodule,” they wrote.

The investigators did not disclose outside funding or conflicts of interest related to their findings.


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