Role of 18F-fluorodeoxyglucose accumulation in radiological ground-glass opacity of non-small cell lung cancer.

Background: This study aimed to elucidate the significance of the maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) by radiological ground glass opacity (GGO) tumors of non-small cell lung cancer (NSCLC), particularly in tumors assumed to be pathologically non-invasive.

Methods: Overall, 709 consecutive patients with GGO-dominant NSCLC who underwent complete resections at three institutions between 2017 and 2022 were included. GGO-dominant tumors and pure GGO tumors were evaluated based on the SUVmax. The adenocarcinoma subtypes were categorized into low, medium, and high grade. The correlation between the SUVmax, pathological malignant grade, and pathological invasive diameter was examined.

Results: In GGO-dominant lung adenocarcinoma, the SUVmax correlated positively with the pathological malignant grade and the pathological invasive diameters (respectively, (P = .0001), (P < .0001)). Similarly, in pure GGO lung adenocarcinoma, the SUVmax correlated positively with the pathological malignant grade. The median pathological invasive diameter was higher in patients with SUVmax ≥ 1.0 compared to those with SUVmax < 1.0 [10 mm vs 0 mm, respectively, (P = .017)].

Conclusions: A higher accumulation of FDG than in the background lung reflects invasive components even in pure GGO areas where only non-invasive components are expected. An FDG-PET/CT can complement the qualitative diagnosis in predicting invasive components with limitations in high-resolution computed tomography alone.