(UroToday.com) The 2023 GU ASCO annual meeting included a session on prostate cancer, featuring a presentation by Dr. Emilio Giunta discussing the impact of 68Ga-PSMA PET/CT in patients with mCRPC treated with enzalutamide. 68Ga-PSMA PET/CT is a highly sensitive diagnostic tool to detect prostate metastatic sites even at low levels of PSA. Dr. Giunta and colleagues evaluated the impact of 68Ga-PSMA PET/CT in patients treated with enzalutamide as first-line therapy for mCRPC.
In an observational prospective study, 67 consecutive mCRPC patients were treated with enzalutamide 160 mg once daily in first-line for mCRPC. 68Ga-PSMA PET/CT was performed at baseline, after 3 months, during follow-up and at PSA/clinical progression. Patients were evaluated on a monthly basis for serological PSA response and safety. These authors measured at baseline the sum of metabolic total volume, mean standardized uptake volume, maximum standardized uptake volume and total lesion activity, which is the product of sum of metabolic total volume and mean standardized uptake volume, for a maximum of 20 lesions. These parameters together with baseline PSA level, Eastern Cooperative Oncology Group performance status (ECOG PS), Gleason Score and age were analyzed by univariate and multivariate Cox regression models as potential predictors of progression-free survival, and overall survival.
At the present analysis, 58 mCRPC patients were considered fully evaluable. The median age was 75 years (range, 47-91), ECOG PS was 0 in 47 cases (81%) and 1-2 in 11 (19%), Gleason Score was <8 in 22 (38%) and 8-10 in 36 (62%), and the median baseline PSA was 2.66 µg/L (range 0.09-197):
The observed median sum of metabolic total volume was 5.73 cm3, median maximum standardized uptake volume of 44.85, median mean standardized uptake volume of 25.80, and median maximum standardized uptake volume and total lesion activity of 59.66. At the median follow-up of 52 months, median progression-free survival was 28.9 months (95% CI 16.3-43.6) and median overall survival was not reached (95% CI 36.8-not reached). In univariate analysis, maximum standardized uptake volume and maximum standardized uptake volume and total lesion activity were significant for progression-free survival (p=0.015 and p=0.001, respectively) and overall survival (p=0.026 and p=0.019, respectively), while mean standardized uptake volume was significant only for overall survival (p=0.028):
On multivariate analysis, maximum standardized uptake volume and total lesion activity only remained significant for progression-free survival (p<0.001) and overall survival (p=0.026). Among these 58 patients, 33 patients (57%) repeated 68Ga-PSMA PET/CT after 1 month of treatment and in 7 patients (21%) there was an observed flare:
Dr. Giunta concluded this presentation discussing the impact of 68Ga-PSMA PET/CT in patients with mCRPC treated with enzalutamide with the following concluding messages:
- The assessment of mCRPC by 68Ga-PSMA PET/CT before starting enzalutamide was associated with longer median progression-free survival and overall survival compared to prior studies using standard imaging only
- Maximum standardized uptake volume and total lesion activity, expression of both volume and intensity of 68Ga-PSMA uptake, appeared the strongest parameter able to predict progression-free survival and overall survival
Presented by: Emilio Francesco Giunta, MD, IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST), Meldola, Italy
Co-Authors: Amelia Altavilla, Paola Caroli, Emanuela Scarpi, Virginia Rossetti, Chiara Casadei, Cristian Lolli, Giuseppe Schepisi, Sara Bleve, Maria Concetta Cursano, Lorenzo Gasperoni, Federica Matteucci, Ugo De Giorgi
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Assistant Professor of Urology, Georgia Cancer Center, Augusta University/Medical College of Georgia, @zklaassen_md on Twitter during the 2023 Genitourinary (GU) American Society of Clinical Oncology (ASCO) Annual Meeting, San Francisco, Thurs, Feb 16 – Sat, Feb 18, 2023.