RT Journal Article SR Electronic T1 Positive predictive value and correct detection rate of 18F-rhPSMA-7 PET in biochemically recurrent prostate cancer validated by composite reference standard JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.120.255661 DO 10.2967/jnumed.120.255661 A1 Maythinee Chantadisai A1 Gabriel Buschner A1 Markus Krönke A1 Isabel Rauscher A1 Thomas Langbein A1 Stephan G. Nekolla A1 Kilian Schiller A1 Matthias M. Heck A1 Tobias Maurer A1 Alexander Wurzer A1 Hans-Juergen Wester A1 Calogero D'Alessandria A1 Wolfgang Weber A1 Matthias Eiber YR 2020 UL http://jnm.snmjournals.org/content/early/2020/11/27/jnumed.120.255661.abstract AB The objective of this retrospective study was to assess the detection rate (DR), positive predictive value (PPV) and correct detection rate (CDR) of 18F-rhPSMA-7 PET/CT in biochemical recurrence (BCR) of prostate cancer (PCa) after radical prostatectomy (RP) using composite validation. Methods: 18F-rhPSMA-7 PET/CT scans of patients with BCR between July 2017 and June 2018 were retrospectively reviewed. All suspicious lesions were recorded. Reference standard was histopathology or combinations of histopathology, imaging or prostate-specific antigen (PSA) follow up, defined as composite reference standard. DR was calculated as the proportion of PSMA PET positive patients to all patients independent of the reference standard, while the CDR was the percentage of patients who had at least one true positive PSMA PET lesion localized that corresponded with the reference standard. The PPV was defined as the proportion of patients who had true positive to all positive findings. The correlation between DR and patient characteristics was evaluated. Results: A total of 532 patients with a median PSA level of 0.97 ng/mL (IQR: 0.41-2.46 ng/mL) were included. Out of these, 162 patients had composite follow-up at a median duration of 5.6 months (range 1.1-14.2 months). The proportion of patients who had no lesion visualized on PET/CT, localized disease, and any distant metastases (M1) were 20%, 43% and 37%, respectively. PET DR among all patients was 80%. On per-patient basis, the PPV of 18F-rhPSMA-7 PET/CT in the composite cohort was 88%, and the CDR was 70%. The PPV in the histopathology-proven cohort was 91%, and the CDR in this subgroup was 73%. In patients with PSA levels ≥1 ng/mL the DR and PPV were 90% and 91%, respectively resulting in a CDR of 82%. In patients with PSA levels <1 ng/mL the DR and PPV were 69% and 85%, respectively resulting in a CDR of 59%. There was a significant positive correlation between 18F-rhPSMA-7 PET/CT detection efficacy and stratified PSA levels (P = 0.005), as well as PSA nadir after prostatectomy (P<0.001). Conclusion: 18F-rhPSMA-7 PET/CT offers high PPV in BCR after RP. Its CDR is dependent on the pre-scan PSA value with excellent CDR in patients with PSA ≥1 ng/mL.