PSMA-ligand PET/CT in patients with biochemical recurrent prostate cancer after radical prostatectomy: matched-pair comparison of ⁶⁸Ga-PSMA-11 and ¹⁸F-PSMA-1007

Purpose: The PSMA ligand ¹⁸F-PSMA-1007 has several principal advantages for imaging prostate cancer when compared to ⁶⁸Ga-PSMA-11. The purpose of this matched-pair analysis was to compare the detection rate of ⁶⁸Ga-PSMA-11 and ¹⁸F-PSMA-1007 PET/CT in patients with recurrent prostate cancer.

Methods: All patients with biochemical recurrent prostate cancer (median PSA-value 0.90 ng/ml, range 0.18-107.70 ng/ml) after radical prostatectomy undergoing ¹⁸F-PSMA-1007 PET/CT at our institution were included in this study (n=102). On the basis of Gleason score, PSA-values, T- and N-stage and antihormonal treatment corresponding ⁶⁸Ga-PSMA-11PET/CT scans were matched based on the institution´s database. Both ⁶⁸Ga-PSMA-11 and ¹⁸F-PSMA-1007 PET/CTs (total n=204) were reviewed by one nuclear medicine physician. PET positive lesions were grouped into a) local recurrence, b) pelvic lymph nodes (LN), c) extra pelvic LN, d) bone and e) others. For each region, SUVmax of the lesion with the highest PSMA-ligand uptake was noted. Detection rates were determined and SUVmax of suspicious lesions were compared.

Results: Overall, patient-based detection rate was 80.4% (82/102) for both ⁶⁸Ga-PSMA-11 and ¹⁸F-PSMA-1007 PET/CT, respectively. In ⁶⁸Ga-PSMA-11 PET, 126 lesions were rated as suspicious for recurrent PC (mean SUVmax 14.7 ± 15.6, range 3.3-112.5), while in ¹⁸F-PSMA-1007 PET 124 lesions were rated as suspicious (mean SUVmax 19.3 ± 29.9, range 2.7-234.4, p= 0.816 for comparison with ⁶⁸Ga-PSMA-11). Sites for suspicious lesions were pelvic LN, local recurrence, extra-pelvic LNM, bone metastases and others in 34%, 25%, 17%, 22% and 2% on ⁶⁸Ga-PSMA-11 PET and 29%, 21%, 28%, 18% and 4% on ¹⁸F-PSMA-1007 PET.

Conclusions: In this matched pair analysis tumor detection rates with ¹⁸F-PSMA-1007 appear similar to ⁶⁸Ga-PSMA-11 in patients with recurrent prostate cancer.