Objective: The purposes of our study were to evaluate 18F-FDG PET findings of ground-glass opacity (GGO) nodules and to determine the value of FDG PET for the preoperative staging of lung cancer manifesting predominantly as GGO.
Materials and methods: Eighty-nine patients (46 men and 43 women; mean [±SD] age, 62.4±7.2 years [range, 33-81 years] and 61.7±6.7 years [range, 34-75 years], respectively) with 134 GGO nodules (56 single and 78 multiple) who underwent CT and FDG PET before surgery were included. CT and PET findings were assessed in terms of lesion size, GGO percentage, multiplicity, and maximum standardized uptake value (SUVmax). SUVmax was correlated with lesion size and GGO percentage using linear regression. The SUVmax and hypermetabolism rates of solitary and multiple GGO nodules were compared using the Student t test or Fisher exact test. Lymph node and distant organ metastasis staging by FDG PET were correlated with histopathologic findings.
Results: SUVmax was positively correlated with lesion size (mean, 14.5 mm; range, 5-37 mm) (r=0.6705; p<0.0001) and was negatively correlated with GGO percentage (mean, 77%; range, 50-100%) (r=-0.7465; p<0.0001). Solitary nodules showed higher hypermetabolism rates (73% [41/56]) than did multiple nodules (27% [21/78]) (p=0.0001), but SUVmax was not significantly different between solitary and multiple nodules. There was no true-positive interpretation of nodal or distant metastasis from GGO nodules by FDG PET.
Conclusion: FDG PET showed no clear advantage for the staging of lung cancer with predominant GGO because of the low incidences of nodal and distant metastasis.