Overestimated value of (18)F-FDG PET/CT to diagnose pulmonary nodules: Analysis of 298 patients

Abstract

Aim: To investigate the accuracy and efficacy of combined 2-[(18)F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)/computed tomography (CT) in the diagnosis of pulmonary nodules.

Material and methods: The present retrospective study included 298 patients with clinically suspected pulmonary malignancy who underwent preoperative PET/CT. The results of PET/CT were compared with the histopathological findings after thoracotomy or thoracoscopic surgery.

Results: Of 298 patients, pulmonary malignancy was histopathologically diagnosed in 248 and benign lesions in 50 patients. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of PET/CT in detecting malignant lesions were 80.2%, 38%, 86.5%, 27.9%, and 73.1%, respectively. The specificity and NPV were very low, and the area under curve (AUC) in the receiver operating characteristic (ROC) curve analysis was 0.694. For 219 patients with non-small cell lung cancer (NSCLC), falsely negative results occurred in 43 patients. The multivariate risk-factor analysis identified high differentiation (p < 0.001), peripheral lung cancer (p = 0.016), non-pleural invasion (p = 0.001), tumour size ≤3 cm (p = 0.026), adenocarcinoma (p = 0.062) and non-smoker (p = 0.066) as risk factors for false negatives..

Conclusion: The study suggests that the role of PET/CT in the detection of pulmonary malignancy has been overestimated in the past. It warrants attention that high differentiation, peripheral lung cancer, non-pleural invasion, tumour size ≤3 cm, adenocarcinoma, and non-smoker were independent risk factors for negative PET/CT findings of NSCLC..