Diagnostic performance of 18 F-PSMA-1007 PET/CT in patients with biochemical recurrent prostate cancer

Abstract

Purpose

The introduction of ligands targeting prostate-specific membrane antigen (PSMA), especially ⁶⁸Ga-PSMA-11, has changed the management of patients with prostate cancer (PCa). ¹⁸F-Labelled ligands can be produced in larger amounts and therefore can improve availability for a larger group of patients. The aim of this study was to evaluate the diagnostic performance of the recently introduced ¹⁸F-PSMA-1007 in patients with recurrent PCa.

Methods

This retrospective analysis included 100 consecutive patients with biochemical relapse (mean age 68.75 ± 7.6 years) referred for PSMA PET/CT. Whole-body PET/CT imaging (from the lower limbs to the skull) was performed in all patients 120 min after injection of 338 ± 44.31 MBq ¹⁸F-PSMA-1007. Prostatectomy, radiation beam therapy of the prostate bed and androgen-deprivation therapy had been performed in 92%, 45% and 27% of the patients, respectively. Radiation beam therapy of the prostate bed had been performed in addition to surgery in 38 patients (38%) and 10 patients (10%) had received all three therapy modalities. The probability of a ¹⁸F-PSMA-1007 PET/CT scan suggestive of pathology was compared with the Gleason score (GS) and PSA level.

Results

Of the 100 patients, 95 (95%) showed at least one pathological finding on ¹⁸F-PSMA-1007 PET/CT. The overall median PSA level was 1.34 ng/ml (range 0,04–41.3 ng/ml). The rates of pathological scans were 86%, 89%, 100% and 100% among patients with PSA levels ≤0.5, 0.51–1.0, 1.1–2.0 and > 2.0 ng/ml, respectively. The median GS was 7 (range 5–10). The majority of patients (70) with a GS available had a score in the range 7–9. The rate of pathological scans in these patients was 93% (65/70). The median SUV_max values of the pathological findings were 10.25, 14.32, 13.16 and 28.87 in patients with PSA levels ≤0.5, 0.51–1.0, 1.1–2.0 and >2.0 ng/ml, respectively. The median SUV_max in patients with a PSA level of >2.0 ng/ml was significantly higher than in all other PSA groups.

Conclusion

¹⁸F-PSMA-1007 PET/CT can detect recurrent PCa in a high percentage of patients with biochemical relapse. The probability of a pathological ¹⁸F-PSMA-1007 PET/CT scan seems to be high even in patients with a low PSA level ≤0.5 ng/ml, and this may have a significant impact on the management of this relevant group of patients.

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