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

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 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..