18F-PSMA-1007 PET/CT at 60 and 120 minutes in patients with prostate cancer: biodistribution, tumour detection and activity kinetics

Detection Rate of 18F-Labeled PSMA PET/CT in Biochemical Recurrent Prostate Cancer: A Systematic Review and a Meta-Analysis

Background: The use of radiolabeled prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) for biochemical recurrent prostate cancer (BRPCa) is increasing worldwide. Recently, ¹⁸F-labeled PSMA agents have become available. We performed a systematic review and meta-analysis regarding the detection rate (DR) of ¹⁸F-labeled PSMA PET/CT in BRPCa to provide evidence-based data in this setting. Methods: A comprehensive literature search of PubMed/MEDLINE, EMBASE, and Cochrane Library databases through 23 April 2019 was performed. Pooled DR was calculated on a per-patient basis, with pooled proportion and 95% confidence interval (95% CI). Furthermore, pooled DR of ¹⁸F-PSMA PET/CT using different cut-off values of prostate-specific antigen (PSA) was obtained. Results: Six articles (645 patients) were included in the meta-analysis. The pooled DR of ¹⁸F-labeled PSMA PET/CT in BRPCa was 81% (95% CI: 71–88%). The pooled DR was 86% for PSA ≥ 0.5 ng/mL (95% CI: 78–93%) and 49% for PSA < 0.5 ng/mL (95% CI: 23–74%). Statistical heterogeneity was found. Conclusions: ¹⁸F-labeled PSMA PET/CT demonstrated a good DR in BRPCa. DR of ¹⁸F-labeled PSMA PET/CT is related to PSA values with significant lower DR in patients with PSA < 0.5 ng/mL. Prospective multicentric trials are needed to confirm these findings.

Intra-individual comparison of 68Ga-PSMA-11 and 18F-DCFPyL normal-organ biodistribution

Purpose

Detailed data comparing the biodistribution of PSMA radioligands is still scarce, raising concerns regarding the comparability of different compounds. We investigated differences in normal-organ biodistribution and uptake variability between the two most commonly PSMA tracers in clinical use, ⁶⁸Ga-PSMA-11 and ¹⁸F-DCFPyL.

Methods

This retrospective analysis included 34 patients with low tumor burden referred for PET/CT imaging with ⁶⁸Ga-PSMA-11 and subsequently ¹⁸F-DCFPyL. Images were acquired with 4 cross-calibrated PET/CT systems. Volumes of interest were placed on major salivary and lacrimal glands, liver, spleen, duodenum, kidneys, bladder, blood-pool and muscle. Normal-organ biodistribution of both tracers was then quantified as SUV_peak and compared using paired tests, linear regression and Bland-Altman analysis. Between-patient variability was also assessed. Clinical and protocol variables were investigated for possible interference.

Results

For both tracers the highest uptake was found in the kidneys and bladder and low background activity was noted across all scans. In the quantitative analysis there was significantly higher uptake of ⁶⁸Ga-PSMA-11 in the kidneys, spleen and major salivary glands (p <  0.001), while the liver exhibited slightly higher ¹⁸F-DCFPyL uptake (p = 0.001, mean bias 0.79 ± 1.30). The lowest solid-organ uptake variability was found in the liver (COV 21.9% for ⁶⁸Ga-PSMA-11, 22.5% for ¹⁸F-DCFPyL). There was a weak correlation between ¹⁸F-DCFPyL uptake time and liver SUV_peak (r = 0.488, p = 0.003) and, accordingly, patients scanned at later time-points had a larger mean bias between the two tracers’ liver uptake values (0.05 vs 1.46, p = 0.001).

Conclusion

Normal tissue biodistribution patterns of ⁶⁸Ga-PSMA-11 and ¹⁸F-DCFPyL were similar, despite subtle differences in quantitative values. Liver uptake showed an acceptable intra-patient agreement and low inter-patient variability between the two tracers, allowing its use as a reference organ for thresholding scans in the qualitative comparison of PSMA expression using these different tracers.

Electronic supplementary material

The online version of this article (10.1186/s40644-019-0211-y) contains supplementary material, which is available to authorized users.

Initial evaluation of PET/CT with 18 F-FSU-880 targeting prostate-specific membrane antigen in prostate cancer patients

This first‐in‐man study was carried out to evaluate the safety, whole‐body distribution, dose estimation, and lesion accumulation of ¹⁸F‐FSU‐880, a newly developed probe targeting prostate‐specific membrane antigen. Six prostate cancer patients with known metastatic lesions underwent serial whole‐body PET/computed tomography (CT) with ¹⁸F‐FSU‐880. Blood and urine were analyzed before and after PET/CT. Accumulation of ¹⁸F‐FSU‐880 in organs and metastatic lesions in serial PET images were evaluated by measuring the standardized uptake values. From the biodistribution data, the organ doses and whole‐body effective dose were calculated using OLINDA/EXM software was developed by Dr. Michael Stabin of Vanderbilt University, Nashville, Tennessee, USA. ¹⁸F‐FSU‐880 PET/CT could be carried out without significant adverse effects. High physiological uptake was observed in the salivary/lachrymal glands and kidneys. The effective dose was calculated to be 0.921 × 10⁻²mSv/MBq. Known metastatic lesions were clearly visualized with high image contrast that increased with time, except in 1 patient, whose bone metastases were well‐controlled and inactive. The PET/CT with ¹⁸F‐FSU‐880 could be carried out safely and could clearly visualize active metastatic lesions. The present results warrant further clinical studies with a larger number of cases to verify the clinical utility of ¹⁸F‐FSU‐880 PET/CT in the management of prostate cancer patients.

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

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.