Radiology. 2015 Sep;276(3):873-82. doi: 10.1148/radiol.2015141071. Epub 2015 Apr 23.
Kakinuma R1, Muramatsu Y1, Kusumoto M1, Tsuchida T1, Tsuta K1, Maeshima AM1, Asamura H1, Moriyama N1.
Purpose
To clarify the percentage of solitary pure ground-glass nodules (SPGGNs) 5 mm or smaller that grow and develop into invasive adenocarcinomas.
Materials and Methods
This study was approved by the institutional review board, and informed consent was obtained from all people who were screened. From February 2004 through December 2007, 7294 participants underwent screening for lung cancer with computed tomographic (CT) imaging. The nodule database was reviewed to identify SPGGNs 5 mm or smaller. Growth of the SPGGNs was evaluated as of March 31, 2013. In cases of pathologic analysis-proven adenocarcinomas that developed from SPGGNs 5 mm or smaller, solid components were evaluated. Percentages, 95% confidence intervals, and means were calculated.
Results
At baseline screening, 438 SPGGNs 5 mm or smaller were identified, and during the study period one SPGGN 5 mm or smaller developed de novo. Of the 439 SPGGNs, 394 were stable and 45 (10.3% [95% confidence interval: 7.5%, 13.7%]), including newly developed SPGGN, grew. Of the 45 SPGGNs that grew, 0.9% (four of 439 [95% confidence interval: 0.3%, 2.3%]) developed into adenocarcinomas (two minimally invasive [including the newly developed SPGGN] and two invasive). The mean period between baseline CT screening and the appearance of solid components in the four adenocarcinomas was 3.6 years.
Conclusion
Of SPGGNs 5 mm or smaller, approximately 10% will grow and 1% will develop into invasive adenocarcinomas or minimally invasive adenocarcinomas. SPGGNs 5 mm or smaller should be rescanned 3.5 years later to look for development of a solid component. (©) RSNA, 2015.