# Article Review: PSMA PET CT in biochemical recurrence of prostate cancer with PSA levels 0 2 ng mL a German multicenter analysis of conventional PSMA tracers including 68Ga Ga PSMA 11 68Ga Ga PSMA I amp T and 18F PSMA 1007

# Objectives
This multicenter study evaluated the detection rates of three Prostate-Specific Membrane Antigen (PSMA) Positron Emission Tomography/Computed Tomography (PET/CT) tracers ([68Ga]Ga-PSMA-11, [68Ga]Ga-PSMA I&T, [18F]PSMA-1007) in 321 patients with Biochemical Recurrence (BCR) of Prostate Cancer (PC) and very low Prostate-Specific Antigen (PSA) levels (≤0.2 ng/mL).
- The core contribution is establishing the overall pooled detection rate (29.6%) in this specific low-PSA cohort.
- It demonstrates comparable diagnostic performance among the three tracers, finding no statistically significant difference between 68Ga-labeled and 18F-labeled tracers in this setting.
- It identifies PSA level >0.15 ng/mL, initial Gleason score >7, and prior Androgen Deprivation Therapy (ADT) as factors associated with significantly higher detection rates.

# Methodology
This study employed a retrospective multicenter analysis design involving five German academic centers. Data from 321 patients with a history of radical prostatectomy and BCR with PSA ≤ 0.2 ng/mL were analyzed. Patients underwent whole-body PET/CT imaging ~60-90 min after injection of one of three tracers: [68Ga]Ga-PSMA-11 (n=170), [68Ga]Ga-PSMA I&T (n=40), or [18F]PSMA-1007 (n=111). All PET/CT scanners were accredited by the European Association of Nuclear Medicine Research GmbH (EARL) initiative.
- The primary endpoint was the overall detection rate of suspicious lesions.
- Secondary endpoints included detection rates stratified by tracer type, PSA level, PSA doubling time (dt), initial Gleason score, and previous therapies (salvage radiation, ADT).
- Statistical analysis used Fisher’s exact test for comparing detection rates among subgroups based on metric scales (PSA, PSA dt) and the Chi-square test for ordinal scales (Gleason score, pretreatment, tracer type).
- The phi coefficient (φ) was used to quantify the strength of association between detection rates and binarized predictor variables.

# Results
The study's core contributions are supported by data from 321 patients.
- The overall pooled detection rate for PSMA PET/CT was 29.6% (95/321).
- No significant difference was found between tracers: [68Ga]Ga-PSMA-11 (29.4%, 50/170), [68Ga]Ga-PSMA I&T (22.5%, 9/40), and [18F]PSMA-1007 (32.4%, 36/111) (p ≥ 0.314). ![](https://media.springernature.com/lw1200/springer-static/image/art%3A10.1007%2Fs00259-025-07292-1/MediaObjects/259_2025_7292_Fig1_HTML.png) ![](https://media.springernature.com/lw1200/springer-static/image/art%3A10.1007%2Fs00259-025-07292-1/MediaObjects/259_2025_7292_Fig2_HTML.png)
- Detection rates increased significantly with PSA levels: 23.3% for PSA <0.1 ng/mL, 25.6% for PSA 0.1-0.15 ng/mL, and 35.6% for PSA >0.15 ng/mL (p=0.029, φ=0.122). ![](https://media.springernature.com/lw1200/springer-static/image/art%3A10.1007%2Fs00259-025-07292-1/MediaObjects/259_2025_7292_Fig3_HTML.png)
- Detection rates were significantly higher for initial Gleason score >7 (38.3%) compared to ≤7 (25.0%) (p=0.018, φ=0.141). ![](https://media.springernature.com/lw1200/springer-static/image/art%3A10.1007%2Fs00259-025-07292-1/MediaObjects/259_2025_7292_Fig5_HTML.png)
- Prior ADT was associated with a higher detection rate (40.3% vs. 26.8%, p=0.031, φ=0.120).
- PSA dt showed a trend but no significant association with detection rate (p=0.077), though data was only available for 149 patients. ![](https://media.springernature.com/lw1200/springer-static/image/art%3A10.1007%2Fs00259-025-07292-1/MediaObjects/259_2025_7292_Fig4_HTML.png)

# Discussions
This study provides valuable real-world data on PSMA PET/CT performance in a challenging low-PSA BCR setting.
Limitations & Suggestions:
- The retrospective design introduces potential selection bias and heterogeneity across centers, although EARL accreditation helps standardize imaging quality.
- Subgroup sizes vary, particularly for [68Ga]Ga-PSMA I&T (n=40) and for analyses requiring complete data (e.g., PSA dt, n=149), which may limit the statistical power for comparisons and subgroup analyses. Missing data were not imputed.
- While no significant difference between tracers was found, the study might be underpowered to detect subtle differences, especially for [68Ga]Ga-PSMA I&T. A prospective, ideally head-to-head comparison within the same patients (if ethically and logistically feasible) or larger matched cohorts, could provide more definitive evidence.
- The analysis focuses on detection rate but lacks multiparametric analysis incorporating other imaging or clinical features, which could potentially improve predictive models for scan positivity.
- Inter-observer variability in image interpretation was not assessed, which is a common limitation in retrospective multicenter studies.

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Reference: [PSMA PET CT in biochemical recurrence of prostate cancer with PSA levels 0 2 ng mL a German multicenter analysis of conventional PSMA tracers including 68Ga Ga PSMA 11 68Ga Ga PSMA I amp T and 18F PSMA 1007](https://link.springer.com/article/10.1007/s00259-025-07292-1)