Analysis of distant metastasis characteristics in hormone-sensitive and castration-resistant prostate cancer based on prostate-specific membrane antigen PET-CT

Metastatic Burden in Hormone-Naive Prostate Cancer: A Tale of Two Subgroups

Prostate cancer (PCa) is the most common malignancy in men aged 50 years and older and the second cause of cancer death among men. Accurate staging of PCa preoperatively is of high importance for treatment decisions and patient management. Conventional imaging modalities (ultrasound, computed tomography [CT], and magnetic resonance imaging) are inaccurate for the staging of PCa. Newer modality multiparametric magnetic resonance imaging (mpMRI) and prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scan show promising results for the staging of PCa. Only fewer studies are available for comparison of these modalities with histopathology as reference. The objective of our study is to evaluate the diagnostic accuracy of independent 68gallium PSMA (68Ga-PSMA) PET-CT compared with mpMRI for preoperative staging of PCa, using histopathology as the reference standard. From August 2021 to December 2022, 30 patients of biopsy-proven PCa were prospectively enrolled as per eligibility criteria. Preoperatively, 68Ga-PSMA PET scan and mpMRI were done in all the patients. Extracapsular extension (ECE), seminal vesicle invasion (SVI), and lymph node metastasis (LNM) were investigated separately. Subsequently, the patients underwent robotic-assisted radical prostatectomy with bilateral pelvic lymph node dissection. mpMRI prostate was more sensitive (66.66%) but less specific than PSMA PET-CT (55.55%) for ECE. mpMRI and PSMA PET-CT both had similar sensitivity (83.3%) and specificity (87.5%) for SVI. PSMA PET-CT was more sensitive (85.71%) and specific (95.6%) than mpMRI prostate (62.5% and 91.30%, respectively) for LNM. PSMA PET-CT is more specific for the detection of ECE and more sensitive and specific for the detection of LNM than mpMRI, and similar for the detection of SVI. mpMRI provides only local staging, while PSMA PET-CT provides information about local, regional, and distal staging. Overall, PSMA PET-CT is superior to mpMRI for locoregional staging of PCa.

Prostate-specific membrane antigen PET-CT in patients with high-risk prostate cancer before curative-intent surgery or radiotherapy (proPSMA): a prospective, randomised, multicentre study

Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer by Pattern of Metastatic Spread: ARCHES Post Hoc Analyses.

18F-fluciclovine PET-CT and 68Ga-PSMA-11 PET-CT in patients with early biochemical recurrence after prostatectomy: a prospective, single-centre, single-arm, comparative imaging trial.

208 Background: It is estimated that within ten years of primary treatment for prostate cancer up to 40% of patients post radical prostatectomy, and up to 50% of patients post radiotherapy will develop disease recurrence. While monitoring of PSA levels is informative of biochemical recurrence, it may precede radiologically detectable recurrence by months to years, and cannot differentiate local/regional recurrence from systemic disease. This represents a management dilemma for treating physicians. The incorporation of PET probes targeting prostate-specific membrane antigen (PSMA) for prostate cancer shows promise for improving the management of patients with prostate cancer, when used alongside existing imaging techniques, like CT, MRI and bone scans. Methods: Retrospective review of all patients referred from our institution for PSMA imaging was carried out. Baseline clinical features were determined and we analyzed impact of PSMA imaging on management outcomes and survival data. Results: 33 patients referred for 68Ga-PSMA-PET imaging were identified. Median age at diagnosis was 65 years (51 -75). The indication for referral in all patients was biochemical recurrence in the absence of radiological evidence of disease by CT imaging and bone scan. Median PSA at time of referral for PSMA scan was 7.3ug/L (1.4ug/L to 87.7ug/L). 100% of patients (n = 33) were upstaged following PSMA imaging, and 30% (n = 10) had more than one site of metastatic disease identified. Most common sites of metastasis were lymph node and bone. Median number of sites of metastatic disease identified by PSMA imaging was one. These results led to a change in management for 96% patients (n = 32). All patients at the time of this review are alive with a median follow up of 13 months, and median progression-free survival of 11 months. Conclusions: PSMA PET-CT directly led to an alteration in the treatment of the majority of patients in this study. This real world data reflects the growing role of PSMA imaging in influencing clinical decisions for prostate cancer patients with biochemical recurrence. Prospective data from randomized studies are awaited to further validate the role of PSMA PET-CT in this patient cohort.

e17060 Background: To explore the prognostic value of the TRAQinform Profile trained on mid-treatment prostate-specific membrane antigen (PSMA) PET/CT (PSMA-PET) when applied to end-of-treatment PSMA-PET (ePET) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with 177Lu-PSMA Radioligand Therapy (PSMA-RLT). Methods: This was a single-center retrospective study. mCRPC patients who underwent PSMA-RLT with available baseline PSMA-PET (bPET) and ePET within 6 mo of the last PSMA-RLT cycle were eligible. Overall survival (OS) from ePET was collected. TRAQinform IQ technology (AIQ Solutions, Madison, WI) was used to conduct lesion region of interest (ROI)-based analyses at bPET and ePET, and changes in SUVmax, SUVmean, volume (cm3), and SUVtotal (SUVmean x volume) across all lesion ROI from bPET to ePET were extracted. Lesion ROI were matched across time points and categorized into new, increasing, stable, decreasing, and disappeared based on changes in SUVtotal. Associations between % new, % increasing, % stable, % decreasing, and % disappeared lesions and OS were evaluated using univariate Cox regression models. This study applied TRAQinform Profile (a random forest model), trained on 185 external PSMA-PET, to generate TRAQinform Profile scores for early identification of optimal vs. suboptimal responders to PSMA-RLT. Associations between TRAQinform Profile scores and OS were evaluated by Kaplan-Meier analysis. Results: Twenty mCRPC patients were included. Thirteen of 20 patients (65%) had died at the last follow-up. The median survival time from ePET was 14.5 mo (IQR, 10.2–44.3). The median number of lesion ROI identified on bPET and ePET were 13.5 (IQR: 5.8-59.5) and 33 (IQR: 2.8-86.3) respectively. The median % changes in SUVmax, SUVmean, volume, and SUVtotal from bPET to ePET were -33.9%, -20.7%, 4.3%, and -13.9% respectively. An increase in percent new and percent new or increasing lesions was associated with a higher risk of death (HR = 1.03; p = 0.002, HR = 1.03; p = 0.003 respectively), while an increase in percent disappeared or decreasing lesions was associated with a lower risk of death (HR = 0.97; p = 0.006). The median TRAQinform Profile score was 0.27, and patients with a TRAQinform Profile score above the median had shorter OS compared with patients with a TRAQinform Profile score below the median (median OS, 10.9 mo [IQR, 5.0-13.3] vs. median OS, 44.3 mo [IQR, 14.5-44.3]; p = 0.02). Conclusions: In this retrospective study of 20 mCRPC patients treated with PSMA-RLT, the TRAQinform Profile score was prognostic for OS. Percent new, percent new or increasing, and percent disappeared or decreasing lesions were significantly associated with OS. Validation in larger, prospective multicentric clinical trials is warranted.

Our objective was to evaluate the prognostic value of end-of-treatment prostate-specific membrane antigen (PSMA) PET/CT (PSMA-PET) in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with 177Lu-PSMA radioligand therapy (PSMA-RLT). Methods: This was a single-center retrospective study. mCRPC patients who underwent PSMA-RLT with available baseline PSMA-PET (bPET) and end-of-treatment PSMA-PET (ePET) within 6 mo of the last PSMA-RLT cycle were eligible. Overall survival (OS) and prostate-specific antigen (PSA) progression status at the time of ePET (by Prostate Cancer Clinical Trials Working Group 3 criteria) were collected. PSMA-PET tumor segmentation was performed to obtain whole-body PSMA tumor volume (PSMA-VOL) and define progressive (≥20% increase) versus nonprogressive disease. Pairs of bPET and ePET were interpreted for appearance of new lesions. Response Evaluation Criteria in PSMA-PET/CT (RECIP) 1.0 were also applied to define progressive versus nonprogressive disease. The associations between changes in PSMA-VOL, new lesions, RECIP 1.0, and PSA progression status at the time of ePET with OS were evaluated by Kaplan-Meier analysis. Results: Twenty mCRPC patients were included. The median number of treatment cycles was 3.5 (interquartile range [IQR], 2-4). The median time between bPET and cycle 1 of PSMA-RLT was 1.0 mo (IQR, 0.7-1.8 mo). The median time between the last cycle of PSMA-RLT and ePET was 1.9 mo (IQR, 1.2-3.5 mo). Twelve of 20 patients (60%) had died at the last follow-up. The median follow-up time from ePET for survivors was 31.2 mo (IQR, 6.8-40.7 mo). The median OS from ePET was 11.4 mo (IQR, 6.8-30.7 mo). Patients with new lesions on ePET had shorter OS than those without new lesions (median OS, 10.7 mo [95% CI, 9.2-12.2] vs. not reached; P = 0.002). Patients with progressive PSMA-VOL had shorter OS than those with nonprogressive PSMA-VOL (median OS, 10.7 mo [95% CI: 9.7-11.7 mo] vs. not reached; P = 0.007). Patients with progressive RECIP had shorter OS than those with nonprogressive RECIP (median OS, 10.7 mo [95% CI, 9.7-11.7 mo] vs. not reached; P = 0.007). PSA progression at the time of ePET was associated with shorter OS (median, 10.9 mo [95% CI, 9.4-12.4 mo] vs. not reached; P = 0.028). Conclusion: In this retrospective study of 20 mCRPC patients treated with PSMA-RLT, progression on ePET by the appearance of new lesions, changes in PSMA-VOL, and RECIP 1.0 was prognostic for OS. Validation in larger, prospective multicentric clinical trials is warranted.

Medication-related osteonecrosis of the jaw (MRONJ) and jaw metastasis might share similar clinical and radiographic characteristics, with both demonstrating F-18 fluorodeoxyglucose (FDG) uptake on PET-CT. Prostate-specific membrane antigen (PSMA) PET-CT is used to demonstrate prostate cancer dissemination. Unlike FDG PET-CT, PSMA PET-CT is more specific to cancer than to inflammation. Therefore, we hypothesized that it might be a useful tool to differentiate between MRONJ and jaw metastasis. All files of prostate cancer patients diagnosed with MRONJ and with available PSMA PET-CT studies were retrieved. A similar number of solid cancer patients with MRONJ and with available FDG PET-CT studies served as a second study group. All studies were reviewed by 2 blinded co-investigators (L.D. and M.F.). Seventeen patients who underwent PSMA PET-CT (24 studies) and 15 patients who underwent FDG PET-CT (29 studies) met the inclusion criteria. All patients with FDG PET-CT studies showed pathological uptake at the site of MRONJ in at least one of their studies versus only 23.5% of patients in the PSMA PET-CT group (P < .001). FDG PET-CT studies showed pathological uptake in 89.6% of the studies compared with only 20.8% in the PSMA PET-CT group (P < .001). The mean standardized uptake value (SUVmax) and the mean uptake volume in the FDG PET-CT group were significantly higher compared with the PSMA PET-CT group (P < .001 and P < .005, respectively). The interclass correlation coefficient for all parameters was higher than 0.95. PSMA PET-CT is useful to differentiate between MRONJ and jaw metastasis.

Targeting Metastatic Hormone Sensitive Prostate Cancer: Chemohormonal Therapy and New Combinatorial Approaches.

First-in-human results of terbium-161 [161Tb]Tb-PSMA-I&T dual beta-Auger radioligand therapy in patients with metastatic castration-resistant prostate cancer (VIOLET): a single-centre, single-arm, phase 1/2 study.

Advanced Prostate Cancer: AUA/ASTRO/SUO Guideline PART II.

To establish a novel quantitative method that automatically excludes the red bone marrow and accurately quantifies the tumor volume on whole-body magnetic resonance imaging using updated imaging software. To also evaluate the association between the quantified tumor volume and the prognosis of patients with metastatic prostate cancer. This prospective analysis included patients diagnosed with metastatic hormone-sensitive or metastatic castration-resistant prostate cancer between 2017 and 2022. We developed an imaging software (Attractive BD_Score) that analyzed whole-body diffusion-weighted and in-phase and opposed-phase T1-weighted images to automatically exclude the red bone marrow. The quantified tumor volume was compared with that quantified by traditional whole-body diffusion-weighted imaging without red bone marrow exclusion. Prostate-specific antigen progression-free survival, time-to-pain progression, and overall survival were evaluated to assess the prognostic value of the quantified tumor volume. The quantified tumor volume was significantly smaller than that quantified by the traditional method in metastatic hormone-sensitive (median: 81.0 ml vs. 149.4ml) and metastatic castration-resistant (median: 29.4 ml vs. 63.5ml) prostate cancer. A highly quantified tumor volume was associated with prostate-specific antigen progression-free survival (p= 0.030), time-to-pain progression (p=0.003), and overall survival (p= 0.005) in patients with metastatic hormone-sensitive prostate cancer and with poor prostate-specific antigen progression-free survival (p= 0.001) and time-to-pain progression (p= 0.005) in patients with metastatic castration-resistant prostate cancer. Our imaging method could accurately quantify the tumor volume in patients with metastatic prostate cancer. The quantified tumor volume can be clinically applied as a new prognostic biomarker for metastatic prostate cancer.

PD22-05 IS PRE OPERATIVE PSMA (PROSTATE SPECIFIC MEMBRANE ANTIGEN) PET/CT A RELIABLE PREDICTOR OF PELVIC LYMPH NODE METASTASIS IN INTERMEDIATE AND HIGH RISK LOCALISED PROSTATE CANCER:A MULTI CENTRE RETROSPECTIVE ANALYSIS

Prostate-specific membrane antigen (PSMA) PET CT is widely used for staging and restaging of prostate cancer. Thyroid and other non-prostatic pathology may be incidentally identified by this imaging modality. Such findings warrant further investigation given their malignant potential. We describe the first reported case of PSMA avid T cell-variant papillary thyroid carcinoma incidentally detected on PSMA PET CT.