Comparison of volume-based and diameter-based assessment of solid nodules in lung cancer screening

Lung cancer screening (LCS) with low-dose CT has been proven to reduce lung cancer-specific mortality in high-risk individuals. However, there has been a lot of concern regarding false-positive scans requiring additional imaging follow-up or even biopsies. Reporting guidelines, such as those developed by the American College of Radiology (ACR Lung-RADS)1 or the British Thoracic Society (BTS),2 aim to reduce false positives and standardise nodule management. Among these guidelines, there is disagreement about how best to measure pulmonary nodules; some, such as the ACR, favour linear diameter measurement, while others, such as the BTS, favour volume measurement. Recently, Creamer et al have compared these two measures as part of a prospective, longitudinal LCS study.3 Through analysis of more than 11 000 baseline LCS CTs, they show that a volume threshold (100 mm3) to ‘rule out’ lung cancer yielded similar sensitivity for cancer as a 6 mm diameter threshold (malignancy risk in negative scans of 0.88% vs 0.81%, respectively). However, the …