Comparing the clinical performance and cost efficacy of [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 in the diagnosis of recurrent prostate cancer: a Markov chain decision analysis

Abstract

Purpose Amongst others, [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 are available for the detection of recurrent prostate cancer (rPC). There are currently limited data comparing the performance of these two radioligands with respect to clinical outcomes or their cost efficacy, which this study aims to address. Methods Two hundred and forty-four patients undergoing PSMA PET/CT for rPC were retrospectively analysed for this study (one hundred and twenty two with each radiopharmaceutical) to generate rates of PET positivity, negativity and unclear findings. Patients underwent follow-up to determine the rate of additional examinations and to confirm PET findings. A Markov chain decision analysis was implemented to model clinical decision-making processes and to analyse clinical performance of the two tracers. We determine their clinical cost efficacies using cost data from several countries where both radiotracers are in routine use. Results The PET positivity rate was non-significantly higher for [18F]PSMA-1007 compared to [68Ga]Ga-PSMA-11 (91.8% vs. 86.9%, p = 0.68), whereas the rate of uncertain findings was significantly greater (17.2% vs. 8.25%, p = 0.02). The probability of a true positive finding was higher for [68Ga]Ga-PSMA-11 (0.90, 95% CI 0.70-0.98) vs. [18F]PSMA-1007 (0.81, 95% CI 0.66–0.91). A significantly (p < 0.0001) higher PPV for [68Ga]Ga-PSMA-11 (0.99, 95% CI 0.99–1.0 vs. 0.86) was found compared to [18F]PSMA-1007 (0.86, 95% CI 0.82–1.00). Intervention efficacy analysis favoured [68Ga]Ga-PSMA-11, where the number needed to image (to achieve a true positive finding) was 10.58 and the number needed to image to harm (to achieve a false positive finding) was − 8.08. A cost efficacy analysis favours [68Ga]Ga-PSMA-11 in three of the four jurisdictions analysed where health economic data was available (Switzerland, Israel, Australia) and [18F]PSMA-1007 in one jurisdiction (Denmark). Conclusion The analysis reveals a non-significantly higher PET positivity rate for [18F]PSMA-1007, but finds significantly greater rates of uncertain findings and false positive findings when compared to [68Ga]Ga-PSMA-11. We find differences in the two tracers in terms of clinical performance and cost efficacy. The method presented herein is generalisable and can be used with clinical or cost data for other countries or tracers.

Diagnostic accuracy of [18F]PSMA-1007 PET/CT in biochemical recurrence of prostate cancer

“…Owing to this lower diagnostic performance in bone lesions, we posit that they are at risk of misclassification in rPC. In particular, FP findings could result in an incorrect staging or require further diagnostic or invasive tests, such as additional imaging or biopsy [ 11 ]. Further studies will be required to demonstrate the magnitude of the clinical impact of uncertain bone lesions.…”

“…This heterogeneous cohort of patients at a variety of stages of rPC and prior treatment furnishes an overview of the radiotracer’s performance under routine clinical conditions. Further studies, for example, directed at early stages of recurrence should be performed, particularly since the PPV, which is dependent upon pre-test prevalence [ 11 ], might be yet lower in these cohorts.…”

“…In addition to [ 68 Ga]Ga-PSMA-11, a large number of alternative radioligands have become available, including but not limited to [ 68 Ga]Ga-PSMA-I&T; [ 68 Ga]Ga-THP-PSMA; and [ 18 F]-labelled PSMA-radiotracers such as [ 18 F]-rhPSMA-7, [ 18 F]-DCFPyL, [18F]-JK-PSMA-7, or [ 18 F]PSMA-1007 [ 5 – 8 ]. Currently, there is only scant evidence to support the choice of one ligand or another [ 9 – 11 ]. [ 18 F]-labelled PSMA-radiotracers have numerous advantages over 68 Ga-labelled ligands: [ 18 F] is cyclotron produced with a longer half live and a lower positron energy compared to [ 68 Ga] (0.65 MeV vs. 1.90 MeV), leading to improved spatial resolution [ 12 ].…”

A randomised, prospective and head-to-head comparison of [68Ga]Ga-PSMA-11 and [18F]PSMA-1007 for the detection of recurrent prostate cancer in PSMA-ligand PET/CT—Protocol design and rationale

“…The first clinically routine PSMA-radio-ligand, [ 68 Ga]Ga-PSMA-11, demonstrated superior diagnostic performance (in terms of detection rate) when compared to a previous generation choline-based radiopharmaceuticals [ 3 ]. More recently, [ 18 F]-labelled radiopharmaceuticals have been introduced and have a number of theoretical advantages compared to 68 Ga. For example, the radiolabel, 18 F, is more easily available and this may improve cost efficacy [ 4 ] as well as theoretically improving image quality through lower positron energy and a longer half-life [ 5 ], although improvements in examination protocols [ 6 ], scanner technology [ 7 ] and cyclotron-produced 68 Ga may limit some of the reported advantages of [ 18 F]-labelled radiopharmaceuticals.…”

“…histology), a multi-reader analysis of the PPV is challenging. Retrospective data from our own group suggest a non-significantly higher detection rate for [ 18 F]PSMA-1007 compared to [ 68 Ga]Ga-PSMA-11 [ 4 ]. We therefore aim to establish the non-inferiority of this new radiopharmaceutical, [ 18 F]PSMA-1007, with respect to the established standard of care [ 68 Ga]Ga-PSMA-11 in terms of PET-positivity rate.…”