A recent meta-analysis comparing ¹⁸F-based prostate-specific membrane antigen (PSMA) radiotracers with [⁶⁸Ga]Ga-PSMA-11 showed no significant differences in clinical impacts between [¹⁸F]DCFPyL and [⁶⁸Ga]Ga-PSMA-11, but deemed [¹⁸F]DCFPyL as a suitable alternative for prostate cancer diagnosis and staging.1

In total, the investigators assessed 24 studies conducted in the past 10 years via the MEDLINE, EMBASE, PubMed, and Web of Science databases. Included studies were those that directly compared 18F-based PSMA radiotracers and [⁶⁸Ga]Ga-PSMA-11 in primary diagnosis and/or secondary staging of prostate cancer following biochemical recurrence. Specifically, the investigators assessed comparisons in normal organ standardized uptake value (SUV) or the lesion SUV or the detection rate.

The investigators found that overall, ¹⁸F-based PSMA radiotracers showed a higher SUVmax and a marginally higher detection rate compared with [⁶⁸Ga]Ga-PSMA-11. However, the authors noted that “these differences were not significant and there is a paucity of high-quality head-to-head comparative data.”

Included in the assessment were several ¹⁸F-based tracers, including [¹⁸F]PSMA-1007, [¹⁸F]DCFPyL, [¹⁸F]JK-PSMA-7, [¹⁸F]rhPSMA-7, and [¹⁸F]AlF-PSMA-11. The 2 most commonly assessed tracers were [¹⁸F]DCFPyL and [18F]PSMA-1007, with [¹⁸F]DCFPyL demonstrating a similar lesion detection rate to [⁶⁸Ga]Ga-PSMA-11 with no increase in false positive rates. A higher detection rate was seen with [¹⁸F]DCFPyL in comparison with [⁶⁸Ga]Ga-PSMA-11, which may be due to the better image spatial resolution by ¹⁸F, the authors noted. [¹⁸F]DCFPyL also showed a similar biodistribution rate to [⁶⁸Ga]Ga-PSMA-11.

They wrote, “Overall, there was not enough evidence in differentiating [¹⁸F]DCFPyL and [⁶⁸Ga]Ga-PSMA-11 in their clinical impacts. The decision to use [¹⁸F]DCFPyL or [⁶⁸Ga]Ga-PSMA-11 is largely based on infrastructure available at the individual health service.”

[¹⁸F]PSMA-1007, however, demonstrated a greater local lesion detection rate vs [⁶⁸Ga]Ga-PSMA-11 due to its predominant hepatobiliary excretory route, according to the authors. Other advantages with [¹⁸F]PSMA-1007 included its accuracy in local lesion delineation. However, the local lesion detection rate was similar with [⁶⁸Ga]Ga-PSMA-11 when patients were administered furosemide prior to the scan. Overall, [¹⁸F]PSMA-1007 was found to be less preferable due to its high benign bone uptakes.

Regarding new ¹⁸F-based PSMA tracers, all 3 assessed ([¹⁸F]JK-PSMA-7, [¹⁸F]rhPSMA-7, and [¹⁸F]AlF-PSMA-11) demonstrated marginally greater detection rates over [⁶⁸Ga]Ga-PSMA-11. When diuretics were administered prior to the scan, [¹⁸F]-rhPSMA-7 demonstrated greater efficacy in detecting lesions adjacent to the bladder, suggesting that the tool may have lower urinary excretion compared with [⁶⁸Ga]Ga-PSMA-11.

The investigators also compared production and cost among the radiotracers, with 1 study showing a cheaper production of [¹⁸F]PSMA-1007 compared with [⁶⁸Ga]Ga-PSMA-11 when assessing the production process, maintenance, and waste disposal. The authors noted that production and transportation of ⁶⁸Ga is more difficult due to the requirement of an on-site generator and its short half-life, respectively.

The authors concluded, “[¹⁸F]DCFPyL was assessed to be a suitable alternative to [⁶⁸Ga]Ga-PSMA-11 in PCa diagnosis and staging due to its similar lesion uptake rate with no increase in benign uptakes. [¹⁸F]PSMA-1007 was assessed to be less preferrable to [⁶⁸Ga]Ga-PSMA-11 due to its significant number of benign bone uptakes.”

References

1. Huang S, Ong S, McKenzie D, et al. Comparison of ¹⁸F-based PSMA radiotracers with [⁶⁸Ga]Ga-PSMA-11 in PET/CT imaging of prostate cancer–a systematic review and meta-analysis. Nature. Published online and accessed November 28, 2023. doi:10.1038/s41391-023-00755-2