Malignant Lung Nodules Detection Improved with PET
A study published in the Journal of Nuclear Medicine indicates that FDG-PET is a more reliable method to detect solitary pulmonary nodules (SPNs) that are malignant compared to CT. Further data from the trial indicates that utilization of a combined-modality approach may improve the rate of early detection. A secondary benefit is the avoidance of unnecessary invasive procedures.
The study described was a large, multi-center effort that was a collaborative effort of ten different VA hospitals across seven states. The trial was completed between January 1999 and June 2001. Over 340 patients with a recent diagnosis of SPN yet to be treated were prospectively enrolled. Patients underwent both CT and fluorine-18 FDG-PET scanning.
Results from the two types of scans were evaluated by expert radiologists. Data was compared to findings from biopsies in 184 cases and follow-up data after two years for 160 patients. The prevalence of malignant lesions in the cohort was 53 percent, most of which were adenocarcinoma or squamous cell carcinoma.
Findings indicate that both CT and PET findings correctly identified those patients who had benign disease, but PET was still more accurate. Of the nodules incorrectly noted to be malignant with CT, PET correctly identified 58 percent as benign. In addition, findings from PET assessment deemed malignant based on SPN-rating criteria were ten times more likely to be malignant than benign after final diagnosis was determined.
The research team further noted that FDG-PET is more likely to identify malignancies correctly at an early stage of disease. Notably, both assessment methods have a high rate of sensitivity and a low rate of false-negatives with respect to the identification of benign lesions. This enables a more conservative approach of waiting, rather than engaging in expensive or invasive follow-up tests.
To date, this is the most rigorous and largest evaluation of PET to detect SPNs. In addition, this is one of the few trials which compared the accuracy of findings from PET and CT.
April 15, 2008 Related topics: Imaging, Diagnostic, Radiology, Hematology & Oncology