Pre-surgical 68Ga-PSMA-11 PET for biochemical recurrence risk assessment: A surrogate of pelvic lymph node dissection? Follow-up analysis of a multicenter prospective phase 3 imaging trial.

Authors

null

Loic Djaileb

UCLA Ahmanson Translational Theranostics Division, LOS Angeles, CA

Loic Djaileb , Wesley Robert Armstrong , Daniel Thompson , Andrei Gafita , Andrea Farolfi , Tristan Grogan , Matthew R. Cooperberg , Peter Carroll , Samuel L. Washington III, Robert Evan Reiter , Matthias Eiber , Ken Herrmann , Wolfgang P. Fendler , Johannes Czernin , Thomas A. Hope , Jeremie Calais

Organizations

UCLA Ahmanson Translational Theranostics Division, LOS Angeles, CA, Ahmanson Translational Theranostics Division, UCLA Nuclear Medicine, Los Angeles, CA, Department of radiology and biomedical imaging. University of California, San Francisco., San Francisco, CA, Ahmanson Translational Theranostics Division, University of California, Los Angeles, CA, Division of Nuclear Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy, University of California Los Angeles, Los Angeles, CA, University of California, San Francisco, San Francisco, CA, UCLA Department of Urology, Los Angeles, CA, Technical University Munich, Munich, Germany, Department of Nuclear Medicine, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Essen, Germany, UCLA Department of Nuclear Medicine, Los Angeles, CA

Research Funding

No funding received
None.

Background: To compare the prognostic value of presurgical PSMA-PET and pelvic lymph nodes invasion (pN1) for biochemical recurrence (BCR) free-survival (FS) in patients with intermediate-risk to high-risk prostate cancer (PCa) treated with radical prostatectomy (RP) and pelvic lymph node dissection. Methods: This is a follow-up study of the surgery cohort included in the multicenter prospective phase 3 imaging trial (n=277; NCT03368547, NCT02611882, NCT02919111). Each 68Ga-PSMA-11-PET scan was read by three blinded independent readers. Local histopathology risk score (CAPRA-S (Cancer of the Prostate Risk Assessment) score without pN data), PSMA-PET extra-prostatic disease (N1/M1), and pN were used to assess risk of BCR. Patients were followed up after RP by the local investigators using electronic medical records. BCR was defined by a prostate-specific antigen (PSA) level ≥0.2 ng/ml after RP or an initiation of PCa specific secondary treatment (>6 months after surgery). Univariate, multivariate Cox model, and c-statistic index were performed to assess the prognostic value of PSMA-PET, LNI and its added value to Local histopathology risk score. Results: From December 2015 to December 2019, 277 patients underwent surgery after PSMA-PET. Clinical follow-up was obtained in 240/277(87%) patients. Median follow-up from surgery was 32.4 (IQR 23.3-42.9) months. Ninety-one/240 BCR events (38%) were observed. PSMA-PET N1/M1 and pN1 were found in 41/240 (17%) and 67/240 (28%) patients respectively. Local histopathology risk score, PSMA-PET and pN were significant univariate predictors of BCR. Only Local histopathology risk score and PSMA PET were significant in multivariate analysis (HR [95% CI] 1.4 (1.2-1.5) p<0.0001) and (1.7 (1-2.9) p=0.03). Prognostic value of model combining local histopathology and PSMA-PET was not significantly different than model combining local histopathology and pN (c-statistic 0.74 (0.69-0.79) vs 0.73 (0.68-0.78); p= 0.69). In patient group with low-risk Local histopathology score and PSMA-PET N0-M0 only 4/109 (5%) were pN1. In patients with high-risk local histopathology score, a PSMA-PET N1/M1 was associated with a significant lower BCR-FS than a PSMA-PET N0-M0 (median survival (95% CI) 32.7 (14.9-NR) vs 8 (3.2-15.5) p= 0.001). pN1 was found in respectively 25/34 (74%) and 34/90 (38%). Conclusions: Combination of pre-surgical PSMA-PET and Local histopathology was not statistically different than the reference standard, i.e local histopathology and pN to predict BCR-FS. Interestingly rate of discrepancy with pN was low among patient with low histopathology risk and PSMA-PET (N0-M0) and patient with high histopathology risk and PSMA-PET (N1/M1). Clinical trial information: NCT03368547.

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Abstract Details

Meeting

2023 ASCO Annual Meeting

Session Type

Poster Session

Session Title

Genitourinary Cancer—Prostate, Testicular, and Penile

Track

Genitourinary Cancer—Prostate, Testicular, and Penile

Sub Track

Prostate Cancer–Local-Regional Disease

Clinical Trial Registration Number

NCT03368547

Citation

J Clin Oncol 41, 2023 (suppl 16; abstr 5090)

DOI

10.1200/JCO.2023.41.16_suppl.5090

Abstract #

5090

Poster Bd #

184

Abstract Disclosures