There are many tools available to evaluate lung cancer patients, including PET scans, CT scans, and clinical history. Mahone and his colleagues from the Department of Radiology, Division of Nuclear Medicine and the Department of Surgery, both at the University of Alabama at Birmingham Medical Center in Birmingham, Alabama, assessed the staging accuracy of PET alone (defined as interpretation of a PET scan along with evaluation of a CT scan performed within one week of PET) versus PET-CT (evaluation of concomitant PET and CT scans from the GE Discovery LS system).
The study evaluated 30 patients undergoing initial staging for non-small cell lung cancer – the most common form of the disease. Patients were injected with the radiopharmaceutical 555 MBq F-18 FDG and underwent a PET-CT scan. These images, as well as the results of the PET scans alone, were compared to pathological specimens.
The results of the study, which were presented at the Society of Nuclear Medicine’s 50th Annual Meeting, revealed that 6.6% of tumors were not classified severely enough based on PET images alone and were correctly upgraded based on PET-CT readings to reflect their actual severity. Mahone and his colleagues attributed PET-CT’s improved accuracy to its ability to identify lung cancer that had spread to the chest wall and other vascular and bronchial structures. In addition, PET readings alone overestimated the severity of some tumors, and combined PET-CT results correctly downgraded 13.3% of tumors. Finally, PET-CT proved more precise in classifying metastasized lung cancer – upstaging cancer that had spread to bones and downstaging cancer that had spread to soft tissue. Overall, the researchers concluded, “PET-CT has greater specificity in staging patients with non-small cell lung cancer.”