Meeting
2023 ASCO Annual Meeting
Early changes of PSMA PET signal after initiation of androgen receptor signaling inhibitors in mCRPC: An international multicenter retrospective study.
Authors
Lena Unterrainer
Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA
Lena Unterrainer , Andrea Farolfi , Florian Rosar , Chloé Santina Denis , Louise Emmett , Ivan de Kouchkovsky , Thomas A. Hope , Masatoshi Hotta , Andrei Gafita , Loic Djaileb , Johannes Czernin , Jeremie Calais
Organizations
Ahmanson Translational Theranostics Division, Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, UCLA, Los Angeles, CA, Division of Nuclear Medicine, IRCCS Azienda Ospedaliero-Universitaria di Bologna, Bologna, Italy, Department of Nuclear Medicine, Saarland University, Homburg, Germany, University of Liège, Liege, Belgium, St. Vincent's Hospital, Sydney, Australia, University of California San Francisco, Helen Diller Family Comprehensive Cancer Center, San Francisco, CA, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, CA, Division of Nuclear Medicine, Department of Radiology, National Center for Global Health and Medicine, Shinjuku-ku, Tokyo, Japan, Tokyo, Japan, Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, Department of Nuclear Medicine, Grenoble Alpes University Hospital, Grenoble, France, Ahmanson Translational Theranostics Division, University of California, Los Angeles, CA
Research Funding
No funding received
None.
Background: Androgen receptor signaling inhibitors (ARSi) play a relevant role in the treatment of prostate cancer. A potential influence of ARSi on PSMA expression has been described. We evaluated early changes of PSMA-expression by PET in mCRPC patients. Methods: This retrospective study included 5 international sites. Patients with mCRPC undergoing 68Ga-PSMA-11 PET/CT prior to (PET1) and early after ARSi (PET2 within 29 days maximum) were included. Whole-body (WB) PSMA-positive tumor volume (PSMA-TV) was evaluated using a liver-specific semi-automatically threshold (Affinity 3.0.2, Hermes Medical Solutions). WB PSMA-TV, SUVmean and SUVmax and their respective changes (%) were analyzed. PSA changes between PET 1 and PET2 were evaluated. Median values and ranges are provided. Results: 54 patients were included in the analysis. ARSi was initiated 1 day (range 0 – 28) after PET1 while PET2 was performed 14 days (range 7 – 29) after ARSi initiation. PSA at PET1 and PET2 was 9.5 ng/ml (range 0.2 – 490.0) and 8.7 ng/ml (range 0.1 – 732.0), respectively (p = 0.035): -33.0% (range -98% – +496%). The WB PSMA-TV at PET1 and PET2 was 89.9 ml (0.0 – 3097.0) and 112.2 ml (0.0 – 3133.0) ml, respectively (p = 0.016; change of +6.0% (range -88% – +260%). WB PSMA SUVmean and SUVmax at PET1 and PET2 was 9.0 (range 5.0 – 43.7) and 9.3 (range 0.0 – 42.5) and 26.5 (range 0.0 – 125.0) and 28.5 (range 0.0 – 212.0), respectively (p = 0.194 and p = 0.353): % change of +3 % (-85% – +71%) and 0% (-55% – +232%). Four of 7 patients with PSA increases at PET2 had an increasing PSMA-TV, 6/7 showed an increasing SUVmean and 5/7 presented with an increased SUVmax. Decreasing WB-PSMA-TV in 18/54 (33%) patients was accompanied by decreasing SUVs in 10 of them (56%). Percent PSA change was unrelated to changes in PSMA-TV, SUVmean and SUVmax. Conclusions: PSMA-PET performed early after ARSI revealed slight increases in the WB-PSMA-TV, stable WB-PSMA SUVs while serum PSA decreased in most of the patients. We conclude that ARSi does not have a strong effect on PSMA expression within 30 days after treatment initiation.
| PET1 | PET2 | Change in % | Significance (p-value) | |
|---|---|---|---|---|
| PSA (ng/ml) | 9.5 (0.2 - 490.0) | 8.7 (0.1 – 732.0) | -33 (-98 – 496) | 0.035* |
| PSMA-TV (ml) | 89.9 (0.0 – 3097.0) | 112.2 (0.0 – 3133.0) | +6 (-88 – 260) | 0.016* |
| SUVmean | 9.0 (5.0 – 43.7) | 9.3 (0.0 – 42.5) | +3 (-85 – 71) | 0.194 |
| SUVmax | 26.5 (0-0 – 125.0) | 28.5 (0.0 – 212.0) | 0 (-55 – 232) | 0.353 |
All values are displayed as median (range). * Statistically significant.
Disclaimer
This material on this page is ©2024 American Society of Clinical Oncology, all rights reserved. Licensing available upon request. For more information, please contact licensing@asco.org
Abstract Details
Session Type
Poster Session
Session Title
Genitourinary Cancer—Prostate, Testicular, and Penile
Track
Genitourinary Cancer—Prostate, Testicular, and Penile
Sub Track
Prostate Cancer– Advanced/Castrate-Resistant
Citation
J Clin Oncol 41, 2023 (suppl 16; abstr 5063)
DOI
10.1200/JCO.2023.41.16_suppl.5063
Abstract #
5063
Poster Bd #
157
Abstract Disclosures
Similar Abstracts
Abstract
2024 ASCO Genitourinary Cancers Symposium
Association between PET-based TheraP eligibility and 177Lu-PSMA-617 (LuPSMA) outcomes in VISION-eligible patients with metastatic castration-resistant prostate cancer (mCRPC).
First Author: Ridvan Arda Demirci
Abstract
2024 ASCO Genitourinary Cancers Symposium
Predictors of PSA response to Lu177-PSMA-617 in metastatic castration-resistant prostate cancer.
First Author: Rebecca Hassoun
Abstract
2024 ASCO Genitourinary Cancers Symposium
Utility of PSMA PET/CT for imaging ductal carcinoma of the prostate.
First Author: Ahmed M. Mahmoud
Abstract
2023 ASCO Annual Meeting
LuPARP: Phase 1 trial of 177Lu-PSMA-617 and olaparib in patients with metastatic castration resistant prostate cancer (mCRPC).
First Author: Shahneen Sandhu