Concordance and Validation of Pre-PET and Post-PET Extent of Suspected Relapse Grouped by Impact of PET Scan
| CSI/PET validation | Impact of PET scan | ||||
|---|---|---|---|---|---|
| High (n = 40) | Medium (n = 8) | Low (n = 13) | None (n = 2) | Total | |
| Concordant | 9 | 3 | 7 | 0 | 19 |
| Both correct | 8 | 1 | 2 | 0 | 11 |
| Neither correct | 1 | 0 | 1* | 0 | 2 |
| Not assessable | 0 | 2 | 4 | 0 | 6 |
| Discordant | 31 | 5 | 6 | 2 | 44 |
| PET correct | 25 | 3 | 2 | 1 | 31 |
| CSI correct | 1 | 0 | 0 | 0 | 1 |
| Both incorrect | 2† | 0 | 2‡ | 0 | 4 |
| Not assessable | 3 | 2 | 2 | 1 | 8 |
↵* Local recurrence was pathologically confirmed at salvage surgery, but adrenal metastasis developed at this location 4 mo after findings were negative on PET and CT.
↵† In both patients, PET correctly excluded relapse at suggestive site found on CT but was incorrect at another site.
↵‡ One patient had false-positive findings on both CT and PET because of changes after radiotherapy, and patient had only equivocal lung metastasis (2 mm) found on CT and was also understaged by PET.
CSI = conventional restaging investigations.