BACKGROUND: The aim of this study is to evaluate the efficacy of positron emission tomography-computed tomography (PET-CT) in the diagnosis of ≤1 cm nodules detected during lung cancer diagnosis.
MATERIALS AND METHODS: Patients with pulmonary parenchymal nodules ≤1 cm during the diagnosis of lung cancer between January 2014 and December 2016 were included in the study. The radiologic (size, location, shape, and contour properties) and radiometabolic (presence of fluoro 2-deoxyglucose [FDG] uptake in the nodule, presence and number of PET-CT mediastinal lymphadenopathy [LAP] uptake, mediastinal LAP maximum standard uptake value [SUVmax], presence and number of PET-CT extrapulmonary metastasis) features of the nodules were recorded. Nodules that were followed for at least 6 months and unchanged in size were considered benign, and those that increased or decreased in size or completely regressed were considered malignant.
RESULTS: Of a total of 167 patients with lung cancer, 116 (69.4%) had no nodules and 51 (30.5%) had nodules. Of the 51 patients with nodules, 27 (53%) had benign and 24 (47%) had malignant nodules. Compared with patients with benign nodules, the FDG uptake rate, SUVmax values, mediastinal LAP uptake in PET-CT, SUVmax value of the mediastinal LAP with uptake, the number of mediastinal LAPs with uptake, and reported the presence and number of extrapulmonary distant organ metastases in PET-CT were statistically significantly higher in malignant nodules (P < 0.05). Moreover, FDG uptake of the nodule in PET-CT and the presence of mediastinal LAP uptake in PET-CT were independent predictors of malignancy of the nodules (P < 0.05).
CONCLUSION: PET-CT parameters other than SUVmax can be used to interpret accompanying nodules smaller than 1 cm in patients with lung cancer.