Detection of lung carcinoma arising from ground glass opacities (GGO) after 5 years - A retrospective review

Pure ground glass opacities (GGO) may indicate pre-invasive subtypes of lung carcinoma. These neoplasms typically demonstrate indolent patterns of growth; Fleischner Society guidelines recommend up to five years of serial imaging. Our aim was to determine the frequency of diagnosed carcinoma arising from GGO detected beyond 5 years of surveillance. We reviewed pathologic diagnoses of lung carcinoma (n = 442) between 2016 and 2018 of a tertiary academic hospital and National Cancer Institute-designated cancer center to identify all cancers that arose from ground glass opacities detected on CT scan. Of the 442 cases of lung carcinoma, 32 (7%) were found that arose from pure GGOs and were ultimately diagnosed as cancer. Among the subgroup of GGOs, 78% (n = 25) were diagnosed within five years of surveillance, but up to 22% (n = 7) required between five and twelve years of serial follow up prior to definitive diagnosis. In order to detect 95% of cancers, GGOs would need to be followed for 7.9-12.7 years based upon a Kaplan-Meier estimate (p = 0.05). No patients who had lung carcinoma arising from GGOs died (0/32) within a follow-up time of one to three years. These data suggest that a greater number of lung carcinomas would be detected upon routine follow up of GGOs that extended beyond the current recommendation of five years. The overall survival of the cohort was 100%, consistent with existing data that these cancers are indolent. It is unknown whether a higher detection rate from longer interval follow up would impact overall survival.