Lung Cancer Deaths in the National Lung Screening Trial Attributed to Nonsolid Nodules

Abstract

Purpose To validate the recommendation of performing annual follow-up of nonsolid nodules (NSNs) identified by computed tomographic (CT) screening for lung cancer, all cases of lung cancer manifesting as NSN in the National Lung Screening Trial (NLST) were reviewed. Materials and Methods Institutional review board and informed consent were waived for this study. The NLST database was searched to identify all participants with at least one NSN on CT scan with lung cancer as the cause of death (COD) documented by the NLST endpoint verification process. Among the 26 722 participants, 2534 (9.4%) had one or more NSNs, and lung cancer as the COD occurred for 48 participants. On review, 21 of the 48 patients had no NSN in the cancerous lobe, which left 27 patients whose CT scans were reviewed by four radiologists: Group A (n = 12) were cases of lung cancer as the COD because of adenocarcinoma, and group B (n = 15) were cases of lung cancer as the COD because of other cell types. Frequency of lung cancer as the COD because of NSN and the time from randomization to diagnosis within these groups was determined. Results Six of the 12 patients in group A had no NSN in the cancerous lobe whereas the remaining six patients had a dominant solid or part-solid nodule in the lobe that rapidly grew in four patients, was multifocal in one patient, and had a growing NSN in one patient in whom diagnosis was delayed for over 3 years. Five of the 15 patients in group B had no NSN, and for the remaining 10 patients, lung cancer as the COD was not because of NSN. Conclusion It seems unlikely that patients with lung cancer as the COD occurred with solitary or dominant NSN as long as annual follow-up was performed. This lends further support that lung cancers that manifest as NSNs have an indolent course and can be managed with annual follow-up. RSNA, 2016.

Controversies on lung cancers manifesting as part-solid nodules

“…For this report, the following definitions were used: Nonsolid nodules (NSNs): Nodules without a solid component that obscures the underlying lung parenchyma other than blood vessels [1, 2, 12] on thin-section CT scans (less than 1 mm) viewed on CT lung window settings. NSNs have also been called “ground-glass opacities (GGOs)”, “pure GGOs”, and “pure ground-glass nodules” [15–18].…”

“…PSNs initially manifest as NSNs and later progress to develop internal solid components [1, 2, 4, 5]. PSNs have also been called “GGOs”, “mixed GGOs”,” mixed tumour with GGO”, “ground-glass nodules,” “mixed nodules,” “part-solid GGO”, “part-solid GGN”, and “partly solid or semisolid” [15–18].…”

Advancing and sharing the knowledge base of CT screening for lung cancer

“…This was quickly accepted by the imaging community and incorporated into the current version of Lung-RADS as well as other authoritative guidelines (20,24) Another example relates to the management of nonsolid nodules where observation on an annual basis is now considered acceptable practice under certain conditions. Again, both the I-ELCAP database and NLST database have been used to confirm this approach (25,26). In the future, continued accrual of screening cases is needed in order to remain current with state-of-the-art technology.…”

Adenocarcinoma in pure ground glass nodules: histological evidence of invasion and open debate on optimal management

“…The reports from lung cancer screening trials showed that conservative management of pGGN provides optimal balance between risk and benefits. In asymptomatic subjects at high risk of lung cancer, pGGN did not progress to advanced stage lung cancer in several years after first documentation on CT (29)(30)(31)(32). Therefore, long-term active surveillance by low-dose CT (LDCT) is encouraged until the evidence of nodule progression.…”