MP18-18: IMPACT OF 18F-DCFPYL PSMA PET ON ACCURACY of mpMRI IN MEN WITH LOW AND INTERMEDIATE RISK PROSTATE CANCER: INTERIM ANALYSIS OF A PHASE II DIAGNOSTIC TRIAL
Friday, May 3, 2024 3:30 PM to 5:30 PM · 2 hr. (US/Central)
302B
Abstract
Best Poster Award Winner
Information
Full Abstract and Figures
Author Block
Marcelo Bigarella*, Edward Lawrence, Abigail Wiedmer, Jenna Cava, Tudor Borza, Igor Bereslavskyy, Madison, WI, Shane Wells, Ann Harbor, MI, Steve Cho, David Jarrard, Madison, WI
Introduction
Next generation PSMA PET imaging is shifting the landscape of prostate cancer (PC), particularly in the setting of initial staging of high-risk patients and recurrence. To evaluate its clinical accuracy in men with low and intermediate risk PC followed on active surveillance (AS) we undertook a prospective trial.
Methods
This IRB-approved prospective Phase II trial tests the diagnostic accuracy of 18F-DCFPyL PSMA PET with mpMRI on a dedicated PET/MRI scanner (GE Healthcare) and systemic and targeted MRI/TRUS prostate biopsy performed. Planned accrual: 100 men on AS and primary outcome is the detection of clinically significant PC (GG/ISUP=2). Blinded GU radiologists interpreted PET (5-point visual Likert scale) and MRI (PI-RADS v2.1) independently. PET SUVmax was obtained for all PIRADS and Likert lesions=3. Standard of care MRI PI-RADS=3 and research PET Likert=3 lesions were biopsied. Per lesion and per patient analyses were performed.
Results
At this interim analysis, 39 patients completed the entire study protocol. Patients had been followed on AS for 23mo(12-47), and most (67%) had low-risk disease. 81 PIRADS=3 lesions were identified on MRI(~2.1/pt), mean size 11(8-15)mm and 71 Likert=3 lesions on PET(~1.8/pt) mean SUVmax 4.4(3.3-6.1). Total lesions for analysis were 107. On study biopsy csPC was found in 16/39(41%) men and 18/107(16.8%) of the targeted lesions. SUVmax of csPC increased with GG (GG2, 3, and 5 were 4.2, 8.8, and 11.1, respectively). The NPV, specificity and accuracy of mpMRI (PI-RADS=3) for csPC was 92%, 27%, 37% respectively and with the addition of PET improved to 95%, 66% and 69% (Table) The addition of PET PSMA detected csPC in 2/16 patients (13%) (GG2, GG3), who would have otherwise continued AS based solely on MRI-targeted biopsies. Avoiding biopsy of PI-RADS=3, Likert=3 lesions would have not missed csPC and saved 4/39(10%) of the patients and 30/107 (28%) lesions from biopsy.
Conclusions
In this interim analysis, the addition of PSMA PET to prostate mpMRI improved the accuracy for csPC detection in men on AS. Imaging and clinical predictive models including PSMA PET with mpMRI may identify men who could safely avoid prostate biopsy and coincident morbidity, as well increasing the detection rates of csPC missed by MRI-biopsy alone.
Source Of Funding
Bluemke Family Fund
Author Block
Marcelo Bigarella*, Edward Lawrence, Abigail Wiedmer, Jenna Cava, Tudor Borza, Igor Bereslavskyy, Madison, WI, Shane Wells, Ann Harbor, MI, Steve Cho, David Jarrard, Madison, WI
Introduction
Next generation PSMA PET imaging is shifting the landscape of prostate cancer (PC), particularly in the setting of initial staging of high-risk patients and recurrence. To evaluate its clinical accuracy in men with low and intermediate risk PC followed on active surveillance (AS) we undertook a prospective trial.
Methods
This IRB-approved prospective Phase II trial tests the diagnostic accuracy of 18F-DCFPyL PSMA PET with mpMRI on a dedicated PET/MRI scanner (GE Healthcare) and systemic and targeted MRI/TRUS prostate biopsy performed. Planned accrual: 100 men on AS and primary outcome is the detection of clinically significant PC (GG/ISUP=2). Blinded GU radiologists interpreted PET (5-point visual Likert scale) and MRI (PI-RADS v2.1) independently. PET SUVmax was obtained for all PIRADS and Likert lesions=3. Standard of care MRI PI-RADS=3 and research PET Likert=3 lesions were biopsied. Per lesion and per patient analyses were performed.
Results
At this interim analysis, 39 patients completed the entire study protocol. Patients had been followed on AS for 23mo(12-47), and most (67%) had low-risk disease. 81 PIRADS=3 lesions were identified on MRI(~2.1/pt), mean size 11(8-15)mm and 71 Likert=3 lesions on PET(~1.8/pt) mean SUVmax 4.4(3.3-6.1). Total lesions for analysis were 107. On study biopsy csPC was found in 16/39(41%) men and 18/107(16.8%) of the targeted lesions. SUVmax of csPC increased with GG (GG2, 3, and 5 were 4.2, 8.8, and 11.1, respectively). The NPV, specificity and accuracy of mpMRI (PI-RADS=3) for csPC was 92%, 27%, 37% respectively and with the addition of PET improved to 95%, 66% and 69% (Table) The addition of PET PSMA detected csPC in 2/16 patients (13%) (GG2, GG3), who would have otherwise continued AS based solely on MRI-targeted biopsies. Avoiding biopsy of PI-RADS=3, Likert=3 lesions would have not missed csPC and saved 4/39(10%) of the patients and 30/107 (28%) lesions from biopsy.
Conclusions
In this interim analysis, the addition of PSMA PET to prostate mpMRI improved the accuracy for csPC detection in men on AS. Imaging and clinical predictive models including PSMA PET with mpMRI may identify men who could safely avoid prostate biopsy and coincident morbidity, as well increasing the detection rates of csPC missed by MRI-biopsy alone.
Source Of Funding
Bluemke Family Fund
Sessions
MP18: Imaging/Uroradiology I
302B