PT  - JOURNAL ARTICLE
AU  - Mena, Esther
AU  - Lindenberg, Maria Liza
AU  - Turkbey, Ismail
AU  - Lin, Frank
AU  - Ton, Anita
AU  - Eclarinal, Philip
AU  - Adler, Stephen
AU  - McKinney, Yolanda
AU  - Weaver, Juanita
AU  - Dahut, William
AU  - Choyke, Peter
TI  - The Role of Castrate Status and Androgen Deprivation Therapy in PSMA-Based <sup>18</sup>F-DCFPyL PET/CT Imaging of Metastatic Prostate Cancer Patients.
DP  - 2021 May 01
TA  - Journal of Nuclear Medicine
PG  - 1357--1357
VI  - 62
IP  - supplement 1
4099  - http://jnm.snmjournals.org/content/62/supplement_1/1357.short
4100  - http://jnm.snmjournals.org/content/62/supplement_1/1357.full
SO  - J Nucl Med2021 May 01; 62
AB  - 1357Objectives: To investigate the performance of 18F-DCFPyL, a Prostate-Specific Membrane Antigen (PSMA) targeted PET agent, in a prospective cohort of patients with documented metastatic prostate cancer (Pca) with androgen deprivation therapy (ADT). The performance of 18F-DCFPyL may depend on patients’ castrate status and time to hormone treatment exposure. Methods: This is a prospective IRB-approved, single-institution study, including 37 patients (median age 69 years-old, median PSA: 6.3 ng/mL; range 0.02-5000 ng/mL). Fourteen patients were metastatic castrate-sensitive Pca (CSPC) and 23 castrate-resistant Pca (CRPC). All patients had prior exposure to ADT and 32 of them were on ADT at the time of the scan. Patients underwent whole-body 18F-DCFPyL-PET/CT at 2 h post-injection (299.9±15.5 MBq). Lesion detection, tumor PSMA-PET standard uptake value (SUV), PSMA-derived tumor volume burden, total lesion PSMA and duration of ADT were assessed and compared between cohorts. Correlations between PET-PSMA parameters and PSA values were also evaluated. Results: 18F-DCFPyL-PET scan detected metastatic disease in all patients, identifying significantly more number of lesions in CRPC patients than in CSPC (15± 77.9 vs 4.0±6.7 lesions, p<0.001) and higher tumor volume burden (36.6±1074 ml vs 19.3±33.2 ml, p<0.05). Tumor PSMA-PET SUVmax was significantly higher in CRPC than in CSPC patients with median SUVmax of 46.9±42.0 vs 20.2±16.4, p=0.002. Total lesion PSMA was higher for CRPC compared to CSPC patients (305.3±5230 vs 59.07±362.1 vs, p<0.05). PSA at the time of scan correlated with total tumor volume burden (r=0.48, p=0.002) for all patients, and with the tumor uptake (SUVmax) for CSPC patients (r=0.66, p=0.007) but not for CRPC patients. The median duration of ADT was 25.4 months, ranging from 1 to 87 months. In patients on ADT at the time of the scan (n=32), the PSMA uptake was lower for early castrate-sensitive patients on short-term ADT (when PSA was below 2 ng/mL) compared to those with advanced disease and long-term ADT (p< 0.05). Patient accrual is ongoing for this trial and more results will be available at the time of presentation. Conclusions: 18F-DCFPyL-PET imaging was able to identify metastatic lesions in patients with castrate-sensitive and castrate-resistant metastatic Pca. In advanced mCRPC, 18F-DCFPyL-PET/CT demonstrated more lesions, with higher tumor volume burden, and higher PSMA-PET uptake than in CSPC patients. For early CSPC patients on short-term ADT (PSA <2 ng/mL), the PSMA uptake was lower than for patients on long-term ADT. The utility of PSMA-targeting imaging in metastatic prostate cancer appears to depend on patient’s castrate status and ADT exposure time.