Patients with Discordant Findings on 18F-NaF PET/CT and 18F-PSMA PET/CT and with Repeated Scans 6 Months Later
| Patient | PSA | cT-stage | ISUP | Treatment between baseline and follow-up scans | Bone metastases on 18F-NaF PET/CT | Bone metastases on 18F-PSMA PET/CT | Bone metastases, reference standard* |
|---|---|---|---|---|---|---|---|
| 36 | 64 | T1c | 3 | EBRT to prostate and pelvic lymph nodes and ADT with LHRH agonist with curative intent | Yes—one lesion near right ischial tuberosity | No—only low uptake near right ischial tuberosity | Yes—increasing uptake on follow-up 18F-NaF and 18F-PSMA; increasing sclerotic appearance |
| 50 | 89 | T4 | 4 | ADT with LHRH agonist. Bicalutamide for 30 d | No | Yes—high uptake in left ilium and low uptake in sacrum | Yes—no change on follow-up 18F-NaF and 18F-PSMA; from all available data, disseminated bone disease on baseline is assumed |
| 79 | 104 | T3b | 5 | ADT with LHRH agonist | No | Yes—multiple small bone metastases | Yes—some lesions (left costa 1 and Th12) become osteoblastic on follow-up CT |
| 86 | 20 | T3a | 5 | Small cell component; treated with ADT (LHRH agonist) and carboplatin and etoposide | No | Yes—small lesion in left femoral neck | No—18F-PSMA uptake becomes slightly faint on follow-up scan; lack of visible 18F-NaF uptake on follow-up is unchanged; no osteoblastic formation |
| 117 | 4.8 | T2c | 4 | EBRT to prostate and pelvic lymph nodes and ADT with LHRH agonist with curative intent | No—uptake in left ilium interpreted benign | Yes—high uptake in left ilium | Yes—lesion becomes faint on follow-up 18F-NaF and 18F-PSMA; small osteoblastic formation |
| 190 | 25 | T2a | 4 | Watchful waiting | No | Yes—high uptake in left ilium and right costa 6 | Yes—new lesion in right ilium on follow-up 18F-NaF and 18F-PSMA; multiple new 18F-PSMA-avid lymph nodes on follow-up |
↵* Reference standard is determined in multidisciplinary team conference and is based on baseline and follow-up PET/CT scans and available clinical data.
PSA = prostate-specific antigen; cT-stage = clinical tumor stage; ISUP = International Society of Urological Pathology; EBRT = external-beam radiation therapy; ADT = androgen deprivation therapy; LHRH = luteinizing hormone–releasing hormone.