Miguel Bronchud, Co-Founder at Regenerative Medicine Solutions, shared on LinkedIn:
“Magnetic resonance Imaging (MRI) is now central to the diagnostic pathway for men with suspected cancer of the prostate.
However, some men have a non-suspicious or equivocal MRI result while still having clinical risk factors that raise concern for clinically significant prostate cancer.
In this setting, prostate ultrasound and biopsy is often recommended- or “fusion ultrasound/MRI” of suspected regions of the prostate- although many biopsies detect no cancer or clinically insignificant disease.
A phase 3 trial evaluated whether [68Ga]Ga-PSMA-11 PET-CT could help guide biopsy decisions in biopsy-naive men with suspected prostate cancer and either PI-RADS 3 MRI findings or PI-RADS 2 MRI findings with additional high-risk clinical features.
The study has obvious limitations but also significant implications. Follow-up is ongoing, and longer-term outcomes are still needed, especially for participants with negative PSMA PET-CT who avoided biopsy.
Besides, this trial focused on men with PI-RADS 2 or PI-RADS 3 MRI findings, so these results do not answer whether PSMA PET-CT can reduce biopsy in men with PI-RADS 4 or PI-RADS 5 findings.
Biopsy data were also often missing in some participants, with a higher proportion in the control group than in the PSMA PET-CT group, and the per-protocol sensitivity analysis had limited interpretability because a substantial proportion of participants were excluded.
The study used [68Ga]Ga-PSMA-11 PET-CT, so the findings cannot automatically be extrapolated to other PSMA radiopharmaceuticals.
Health-economic analyses are also needed to better understand whether the cost of PSMA PET-CT could be offset by fewer biopsies.
The original article, titled “Effect of [68Ga]Ga-PSMA-11 PET-CT in the diagnosis of prostate cancer in men with equivocal or clinically high-risk non-suspicious findings on multiparametric MRI (PRIMARY2): a multicentre, non-inferiority, phase 3, randomised controlled trial,” was published in The Lancet Oncology on June 10, 2026.
PRIMARY2 was an investigator-initiated, multicentre, non-inferiority, phase 3 randomised controlled trial conducted at seven hospitals in Australia. Eligible participants were biopsy-naive men with clinical suspicion of significant prostate cancer, PSA of 20 ng/mL or less, clinical T2 disease or less, and either equivocal PI-RADS 3 MRI or non-suspicious PI-RADS 2 MRI with at least one high-risk feature, such as PSA density greater than 0.1 ng/mL/mL, abnormal digital rectal examination, strong family history, BRCA mutation, PSA greater than 10 ng/mL, PSA doubling time shorter than 36 months, or PSA velocity greater than 0.75 ng/mL per year.”
Title: Effect of [68Ga]Ga-PSMA-11 PET-CT in the diagnosis of prostate cancer in men with equivocal or clinically high-risk non-suspicious findings on multiparametric MRI (PRIMARY2): a multicentre, non-inferiority, phase 3, randomised controlled trial
Authors: James P Buteau, Daniel Moon, Michael T Fahey, Matthew J Roberts, Narjess Ayati, Nathan Papa, Declan G Murphy, Veeru Kasivisvanathan, Haryana M Dhillon, Yang T Du, Philip Dundee, Jessica Foudoulis, David Hennes, Anthony C Hutton, Jordan Idiare, Greg Jack, Sheshang Kamath, Sophie N Lee, Su-Faye Lee, Sze Ting Lee, Scott Leslie, Sidney M Levy, Emma Link, Catherine Mitchell, Joshua J Morigi, Andrew Nguyen, Joanna Olphert, Manish I Patel, David A Pattison, Adam Pearce, Marlon Perera, Ruban Thanigasalam, Alice Thomson, John Yaxley, James Thompson.
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