FDG PET assessment of SPN in WA: stage 4 findings

Objective: The sensitivity of PET in the assessment of a solitary pulmonary nodule (SPN) in Western Australia was reported at two separate scientific meetings, with both reporting cases of stage 4 disease higher than that reported elsewhere. The objective of this review is to determine the true status of these cases.

Methods: A retrospective analysis of all patients referred for assessment of SPN to the WA PET/Cyclotron Service from November 2002 to July 2005, that were reported by PET to be stage 4 disease, was performed. The CT, PET and clinicopathologic outcomes both before and after PET imaging for a period of 2 years post-PET were used in determining the final staging for each case.

Results: Of the 150 patients referred for SPN assessment, over 20% were reported by PET as stage 4 disease. Results indicated that a number of cases were incorrectly referred as SPN by the referring clinician or incorrectly reported as stage 4 disease by PET. A proportion of cases were true stage 4 disease, with the percentage aligned with other reported data. Some errors may have been avoided if pre-PET investigations had been performed or available to the PET clinician.

Conclusion: The results of this study emphasise the important that adequate investigations be performed prior to a PET referral, and be made available to the reporting PET clinician. There will be further investigation into a suitable protocol or clinical pathway for SPN assessment, coupled with clinician involvement and training.