Staging Of High-risk Prostate Cancer Research Articles

P112 Whole-body MRI vs. 68Ga-PSMA PET/CT for staging of high-risk prostate cancer

P112 Whole-body MRI vs. 68Ga-PSMA PET/CT for staging of high-risk prostate cancer

Comparative Performance of 68Ga-PSMA-11 PET/CT and Conventional Imaging in the Primary Staging of High-Risk Prostate Cancer Patients Who Are Candidates for Radical Prostatectomy.

This prospective study aimed to (1) compare the diagnostic performance of 68Ga-PSMA-11 PET/CT with respect to conventional imaging (computed tomography (CT) and bone scintigraphy (BS)) in the primary staging of high-risk prostate cancer (PCa) patients and (2) validate PSMA-PET/CT accuracy in pelvic nodal staging in comparison with postoperative histopathology and assess PSMA-PET/CT's impact on patient management. Sixty castration-sensitive high-risk (ISUP 4-5 and/or PSA > 20 ng/mL and/or cT3) PCa patients eligible for radical prostatectomy were enrolled (median PSA 10.10 [IQR: 6.22-17.95] ng/mL). PSMA-PET/CT, compared with CT, identified nodal (N) and/or distant metastases (M1) in 56.7% (34/60) vs. 13.3% (8/60) (p < 0.001) of patients: N + 45% vs. 13.3% (p < 0.001), M1a 11.7% vs. 1.7% (p = 0.03), M1b 23.3% vs. 1.7% (p < 0.001). Compared with BS, PSMA-PET/CT localized unknown skeletal metastases in 15% (9/60) of cases, with no false negative findings. Overall, PSMA-PET/CT led to a TNM upstaging in 45.0% (27/60) of cases, with no evidence of downstaging, resulting in a change in management in up to 28.8% (17/59) of patients. Compared with histopathology data (n = 32 patients), the per-patient accuracy of PSMA-PET/TC for detecting pelvic nodal metastases was 90.6%. Overall, the above evidence supports the use of PSMA-PET/CT in the diagnostic workup of high-risk prostate cancer staging.

Prostate-Specific Membrane Antigen PET/CT Detection of Prostate Cancer Metastasis to Thyroid and Cricoid Cartilages.

Prostate-specific membrane antigen (PSMA) PET/CT has revolutionized the imaging of prostate cancer. Historically, prostate cancer metastasis to thyroid and cricoid cartilages was thought to be exceedingly rare, with only a few reported cases in the literature. Prostate cancer metastasis to the laryngeal cartilages was detected in 4 of 221 patients who underwent imaging with 18 F-PSMA (Pylarify) or 68 Ga-PSMA (Illuccix) PET/CT for initial staging of high-risk prostate cancer or restaging evaluation in the setting of biochemical recurrence from April 2022 through October 2023. The increased sensitivity and specificity of PSMA PET/CT allow for the detection of previously occult metastatic disease.

Cost analysis of next-generation imaging in high-risk prostate cancer staging

Introduction and objectiveNext-generation imaging (NGI) tests, such as choline PET/CT and PSMA PET, have shown to increase sensitivity in the detection of nodal and metastatic disease in prostate cancer. However, their use implies an increase in diagnostic costs compared to conventional imaging (CI) tests such as CT and bone scan. The aim of our study was to determine which diagnostic pathway is more cost-effective in high-risk prostate cancer. Material and methodCost-effectiveness analysis of the available imaging tests (CI, Choline/PSMA PET) for the staging of high-risk prostate cancer. Sensitivity and specificity were estimated based on published evidence, and costs were collected from the Management Department. In order to carry out a cost-effectiveness analysis, five diagnostic pathways were proposed estimating the accurate diagnoses. ResultsPSMA PET was the most accurate diagnostic option. The CI diagnostic workup was the most economical and CI+PSMA the most expensive. Analyzing the diagnostic cost-effectiveness ratio, CI+PSMA proved to be the most expensive (€5627.30 per correct diagnosis) followed by PET PSMA (€4987.11), choline (€4599.84) and CI (€4444.22). ConclusionsPSMA PET is the most accurate strategy in staging distant disease in patients with high-risk prostate cancer. Radiotracer uptake tests such as CI have been shown to be the most cost-effective option, followed by choline and PSMA.

Análisis de coste de pruebas de nueva generación en estadificación de pacientes con cáncer de próstata de alto riesgo

Introduction and objectiveNext-generation imaging tests, such as choline PET/CT and PSMA PET, have shown to increase sensitivity in the detection of nodal and metastatic disease in prostate cancer. However, their use implies an increase in diagnostic costs compared to conventional imaging (CI) tests such as CT and bone scan. The aim of our study was to determine which diagnostic pathway is more cost-effective in high-risk prostate cancer. Material and methodCost-effectiveness analysis of the available imaging tests (CI, Choline/PSMA PET) for the staging of high-risk prostate cancer. Sensitivity and specificity were estimated based on published evidence, and costs were collected from the Management Department. In order to carry out a cost-effectiveness analysis, five diagnostic pathways were proposed estimating the accurate diagnoses. ResultsPSMA PET was the most accurate diagnostic option. The CI diagnostic workup was the most economical and CI+PSMA the most expensive. Analyzing the diagnostic cost-effectiveness ratio, CI+PSMA proved to be the most expensive (€5627.30 per correct diagnosis) followed by PET PSMA (€4987.11), choline (€4599.84) and CI (€4444.22). ConclusionsPSMA PET is the most accurate strategy in staging distant disease in patients with high-risk prostate cancer. Radiotracer uptake tests such as CI have been shown to be the most cost-effective option, followed by choline and PSMA.

Impact of piflufolastat F-18 PSMA PET imaging on clinical decision-making in prostate cancer across disease states: A retrospective review.

Piflufolastat F-18 (18F-DCFPyL) prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging is approved by the US food and drug administration for initial staging of high-risk prostate cancer, biochemical recurrence (BCR), and restaging of metastatic prostate cancer. Here, we sought to assess how its integration into clinical care may have impacted the management of patients. We identified 235 consecutive patients who underwent an 18F-DCFPyL PET scan from August 2021 to June 2022. The median prostate-specific antigen at the time of imaging was 1.8 ng/mL (Range: 0-3740 ng/mL). Descriptive statistics were used to analyze its impact on clinical care for a subset of 157 patients with available treatment information: 22 for initial staging, 109 with BCR, and 26 patients with known metastatic disease. PSMA-avid lesions were detected in 154/235 (65.5% of) patients. In patients undergoing initial staging, 18/39 (46.2% of) patients had extra-prostatic metastatic lesions; 15/39 (38.5% of) scans were negative and 6/39 (15.4%) had equivocal results. 12/22 (54.5% of) patients had a change in their treatment plan post-PSMA PET scan while 10/22 (45.5%) had no change in their treatment plan. In the BCR cohort, 93/150 (62.0%) had a local recurrence or metastatic lesions. Equivocal and negative scans accounted for 11/150 (7.3%) and 46/150 (30.7%) of scans, respectively. 37/109 (33.9% of) patients had a change in their treatment plan, while treatment was not altered in 72/109 (66.1% of) cases. In patients with metastatic disease, 43/46 (93.5%) had PSMA-avid lesions identified; equivocal and negative scans accounted for 2/46 (4.3%) and 1/46 (2.2%) of scan results, respectively. 6/26 (23.1%) had their tentative treatment plan adjusted after the PSMA PET scan. No change in the treatment plan was observed in 20/26 (76.9% of) cases. Integration of F-18 PSMA PET imaging impacted clinical decision-making and subsequent management across all stages of prostate cancer. It remains to be seen whether this translates into superior survival outcomes.

The impact of F-18 PSMA PET imaging on clinical decision-making in prostate cancer across disease states.

63 Background: Piflufolastat F-18 (18F-DCFPyL) PSMA PET imaging was recently approved by the FDA for initial staging, biochemical recurrence (BCR), and restaging of metastatic prostate cancer. Given that the PSMA PET is a next-generation novel imaging modality that carries a higher sensitivity for detecting metastatic disease compared with conventional imaging, we aimed to assess how its integration into clinical care may have impacted the management of patients. Methods: We identified 236 patients who underwent an 18F-DCFPyL PET scan at the University of Minnesota between August 2021 to June 2022. The median PSA at the time of imaging was 1.75 ng/ml (range, 0.02 - 3740 ng/ml). All PSMA PET scans were evaluated by an experienced nuclear medicine physician. Descriptive statistics were used to analyze its impact on the clinical care of 158 patients: 22 for initial staging, 110 with biochemical recurrence, and 26 patients with known metastatic disease. The remaining 78 patients had no information available to assess clinical utility. Results: Metastatic PSMA-avid lesions were detected in 152/236 (64.4%) patients. In patients undergoing initial staging of high-risk prostate cancer, 17/40 (42.5%) patients had metastatic lesions outside the prostate involving 10 regional and 5 non-regional lymph nodes, 1 visceral site, and 10 bone metastases. 17/40 (42.5%) of the scans were unremarkable. 6/40 (15%) had equivocal scan results. For the patients with available clinical information, 12/22 (54.5%) had a change in their treatment plan post-DCFPyL, while 10/22 (45.5%) had no change. In the biochemical recurrence cohort, 93/151 (61.6%) had positive lesions: 28 local recurrences, 47 regional and 22 non-regional lymph nodes, 5 visceral and 28 bone metastases. Equivocal and negative scans accounted for 13/151 (8.6%) and 45/151 (29.8%) cases, respectively. 44/110 (40%) of the patients with clinical information had a change in their treatment plan, while the plan did not change for 66/110 (60%) cases. In patients with known metastatic prostate cancer undergoing restaging, 42/45 (93.3%) had DCFPyL-positive lesions; 12 local recurrences, 20 regional and 16 non-regional, 9 visceral, and 29 bone metastases. Equivocal and negative scans accounted for 2/45 (4.4%) and 1/45 (2.2) of cases, respectively. Only 11/26 (42.3%) of those with clinical information had their tentative treatment plan adjusted post-DCFPyL. No change in the treatment plan was made in 15/26 (57.7%) cases. Conclusions: Integration of the F-18 PSMA PET imaging substantially impacted clinical decision-making, especially for initial staging of high-risk localized disease (treatment change in 55%) and for biochemical recurrence (treatment change in 40%). It remains to be seen if this would translate into superior survival outcomes.

68Ga-PSMA PET/CT and Prostate Cancer Diagnosis: Which SUVmax Value?

To evaluate the diagnostic accuracy of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in the diagnosis and staging of prostate cancer (PCa). From January 2021 to December 2022, 160 men (median age: 66 years) with PCa (median PSA of 11.7 ng/ml) before prostate biopsy underwent 68Ga-PET/CT imaging examinations (Biograph 6; Siemens, Knoxville, TN, USA). The location of focal uptake on 68Ga-PSMA PET/TC and standardized uptake values (SUVmax) were reported on a per-lesion basis for each International Society of Urological Pathology (ISUP) grade group (GG) PCa. Overall, the median intraprostatic 68Ga-PSMA SUVmax was 26.1 (range=2.7-164); in the 15 men with not clinically significant PCa (ISUP grade group 1) median SUVmax was 7.5 (range=2.7-12.5). In the 145 men with csPCa (ISUP GG≥2) median SUVmax was 33 (range=7.8-164). A SUVmax cut-off of 8 demonstrated a diagnostic accuracy in the diagnosis of PCa equal to 87.7% vs. 89.3% vs. 100% in the presence of a GG1 vs. GG2 vs. GG≥3 PCa, respectively. In addition, median SUVmax in the bone and node metastases was 52.7 (range=25.3-92.8) and 47 (range=24.5-65), respectively. 68GaPSMA PET/CT with a SUVmax cut-off of 8 demonstrated a good accuracy in the diagnosis of csPCa (100% in the presence of GG≥3) showing a good cost-benefit ratio as a single procedure for the diagnosis and staging of high-risk PCa.

68Ga-PSMA PET-CT and PSMA score affecting therapeutic decision-making in high-risk prostatic carcinoma.

This research study was conducted to evaluate the impact of (68Ga)-tagged prostatic-specific membrane antigen (68Ga-PSMA) positron emission tomography and computed tomography (PET-CT), compare its role with conventional radiology in early staging of high-risk prostate cancer, and calculate the PSMA score evaluating its usefulness in 68Ga-PSMA PET-CT reporting in our patient population. 68Ga-PSMA PET-CT of 65 high-risk cases of prostate cancer was performed for staging purpo-ses. Any change in disease stage was noted after 68Ga-PSMA PET-CT findings and PSMA score leading to a change in the management plan. Change in disease stage post-PSMA imaging was seen in 39% cases, high PSMA score (03) was noted in > 80% of upstaged cases, while low score (0) and (1) was seen in 65% and 35% down-staged individuals, respectively. Change in therapeutic decision-making was observed in 32% (21) of patients. 68Ga-PSMA PET-CT scans have a significant influence on the planned clinical management of high-risk prostate cancer patients; hence, they can be utilized as a replacement for radiological imaging tools, particularly in the detection of pelvic nodal and distant metastatic disease. PSMA score can be considered as an effective tool in standardized reporting of 68Ga-PSMA imaging.

Recurrence rate after radical prostatectomy following primary staging of high-risk prostate cancer with 68Ga-PSMA PET/CT

Background Accurate primary staging is one of the most important issues for initial management of prostate cancer (PCa) patients to perform an optimal selection of patients for curative intended treatment. 68Ga-Prostate-Specific-Membrane-Antigen (PSMA) PET/CT was found superior to conventional imaging both for detection of recurrence after curative intended treatment and for primary staging. We studied the recurrence rate after radical prostatectomy in high-risk PCa patients primary staged with 68Ga-PSMA PET/CT compared with conventional imaging. Material and methods The study included 247 D’Amico high-risk PCa patients treated with radical prostatectomy (RP) after primary staging with 68Ga-PSMA PET/CT and a reference group of 137 high-risk patients with RP after conventional imaging (99mTc bone scintigraphy and CT). Recurrence rates were assessed by Cox regression and Kaplan-Meier analysis. Results The 5-year recurrence-free survival rate was 71.1% in the 68Ga-PSMA PET/CT cohort compared with 56.4% in the conventional imaging cohort. Primary staging by 68Ga-PSMA PET/CT reduced biochemical recurrence (BCR) risk by 42% (HR = 0.58 (0.41–0.83), p = .004). Conclusion The present data could indicate a lower recurrence rate after RP following primary staging with 68Ga-PSMA PET/CT compared to conventional imaging, likely due to improved selection of patients for surgery.

Use of 18F-NaF PET in the staging of skeletal metastases of newly diagnosed, high-risk prostate cancer patients: a nationwide cohort study

ObjectiveTo determine whether preoperative staging of high-risk prostate cancer with 18F-sodium-fluoride (18F-NaF) positron emission tomography (PET) reduces the risk of skeletal metastases.DesignNationwide, population-based cohort study using real-world data.SettingThe study used...

18F-Fluciclovine versus PSMA PET Imaging in Primary Tumor Detection during Initial Staging of High-Risk Prostate Cancer: A Systematic Review and Meta-Analysis.

Purpose Fluorine 18 (18F)-fluciclovine and prostate-specific membrane antigen (PSMA) tracers are commonly used for localizing biochemical recurrence of prostate cancer, but their accuracy in primary tumor detection in the initial staging of high-risk prostate cancer has not been established. Materials and Methods A systematic review was performed of the electronic databases for original studies published between 2012 and 2020. Included studies were those in which 18F-fluciclovine or PSMA PET was used for initial staging of patients with high-risk prostate cancer. The diagnostic performance data were collected for primary tumor with histopathologic results as reference standard. The Quality Assessment of Diagnostic Accuracy Studies-2 tool was used for quality appraisal. A random-effects model was used to summarize the effect sizes and to evaluate the difference between two groups. Results Overall, 28 studies met the eligibility criteria, and 17 were included in the meta-analysis (18F-fluciclovine = 4, PSMA = 13). Of these 17 studies, 12 (70%) were judged to have high risk of bias in one of the evaluated domains, and nine studies were deemed to have applicability concerns. The pooled sensitivity, specificity, and diagnostic odds ratio for 18F-fluciclovine versus PSMA were 85% (95% CI: 73%, 92%) versus 84% (95% CI: 77%, 89%) (P = .78), 77% (95% CI: 60%, 88%) versus 83% (95% CI: 76%, 89%) (P = .40), and 18.88 (95% CI: 5.01, 71.20) versus 29.37 (95% CI: 13.35, 64.60) (P = .57), respectively, with no significant difference in diagnostic test accuracy. Conclusion 18F-fluciclovine and PSMA PET demonstrated no statistically significant difference in diagnostic accuracy in primary tumor detection during initial staging of high-risk prostate cancer. Keywords: PET, Prostate, Molecular Imaging-Cancer, Staging Supplemental material is available for this article. © RSNA, 2022.

Should 68Ga-PSMA PET/CT Replace CT and Bone Scan in Clinical Staging of High-risk Prostate Cancer?

To evaluate the accuracy of 68Gallium prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) vs. CT combined with bone scan in the clinical staging of high-risk prostate cancer (PCa). From January 2020 to October 2021, 30 patients underwent clinical staging according to 68Ga-PSMA PET/TC, lung-abdominal CT and Technetium-99m bone scan. 68Ga-PSMA PET/CT demonstrated a better accuracy in comparison with CT plus bone scan in the diagnosis of node metastases at definitive histology (76.9% vs. 46.1%; p=0.001). The 68Ga-PSMA PET/CT was more accurate than CT and bone scan in the staging of high-risk PCa, leading to a change in the therapeutic strategy in 10% of the cases.

68 Ga-PSMA PET/CT for preoperative lymph nosde staging of high-risk prostate cancer.

38 Background: The present study evaluates the potential role of 68Ga-PSMA PET/CT to detect pelvic lymph node metastases in newly diagnosed, treatment-naïve high risk prostate cancer (PCa) patients prior to radical prostatectomy and extended pelvic lymphadenectomy. Methods: A total of 165 men with newly diagnosed high risk PCa (ISUP grade 4/5, PSA &gt; 20 ng/ml or ≥cT3a) were included in this retrospective analysis. All men had undergone a transperineal MR fusion biopsy and all men underwent RPE with epLND. Patients with neoadjuvant ADT, TRUS guided biopsies, previous radiation or surgeries in the small pelvis were excluded. Imaging findings and pathohistological findings were correlated and sensitivity, specificity, positive and negative predictive values were calculated. The correlation of clinical and biopsy characteristics with PSMA PET/CT. Results: The median PSA was 24.5 (6.7-185) ng/ml, the median number of dissected lymph nodes was 21-5 (14-45). A total of 68/165 (41,2%) patients had lymph node metastases (LNM) of which 43 (63.2%) were positive on PSMA-PET/CT whereas 25 (36.8%) LNM were negative on PSMA PET/CT. 97/165 (58.8%) pts had pN0 disease of whom 93 (95.9%) and 3 (4.1%) demonstrated negative and positive PSMA PE/CT findings, resp. n = 47 had positive PSMA PET/CT and 40 (85.1%) demonstrated LNM, 7 (14.9%) had pN0 disease. N = 118 had negative PSMA PET/CT of which 93 (78.8%) and 25 (21.2%) were true and false negative, resp. Sensitivity was 63.2%, specificity was 97.0%, and positive and negative predictive values were 93.5% and 78,8%, respectively. 3564 lymph nodes were resected, 149 (4.2%) had LNM. 88/149 (59.1%) were detected on PSMA PET/CT and 61 (40.9%) were undetected. On a per lymph node base, sensitivity and specificity were 40.4% and 94.5%, resp; positive and negative predictive values were 59.1% and 97.3%. Conclusions: PSMA-PET/CT has a high reliability to identify patients with high risk PCA and LNM. If a positive lesion is detected, epLND is mandatory due to high frequency of undetected small LNM. PSMA-PET/CT, is superior to standard imaging and it might replace CT/MRI of the small pelvis.

Prostate-specific Membrane Antigen Positron Emission Tomography, Not Conventional Imaging, Should Be Performed for Primary Staging of High-risk Prostate Cancer

Prostate-specific Membrane Antigen Positron Emission Tomography, Not Conventional Imaging, Should Be Performed for Primary Staging of High-risk Prostate Cancer

Prostate-specific Membrane Antigen Positron Emission Tomography, Not Conventional Imaging, Should Be Performed for Primary Staging of High-risk Prostate Cancer

Prostate-specific Membrane Antigen Positron Emission Tomography, Not Conventional Imaging, Should Be Performed for Primary Staging of High-risk Prostate Cancer

Utility of 18F-Fluciclovine PET/MRI for Staging Newly Diagnosed High-Risk Prostate Cancer and Evaluating Response to Initial Androgen Deprivation Therapy: A Prospective Single-Arm Pilot Study.

BACKGROUND. Despite advances in prostate cancer treatment, rates of biochemical recurrence remain high, relating to lack of detection of small-volume metastatic disease using conventional imaging for initial staging. OBJECTIVE. The purpose of this study was to assess the potential use of 18F-fluciclovine PET/MRI for initial staging of high-risk prostate cancer and evaluating response to androgen deprivation therapy (ADT). METHODS. This prospective clinical trial enrolled 14 men with newly diagnosed high-risk prostate cancer and negative or equivocal conventional staging imaging for metastatic disease between January 2018 and February 2019. All patients underwent pretreatment 18F-fluciclovine PET/MRI including multiparametric prostate MRI; 12 underwent 18F-fluciclovine PET/MRI after surgery or between ADT and radiotherapy. Confidence in identification of the primary intraprostatic lesion and nodal metastases was independently rated on a 0-3 Likert scale by three readers with nuclear medicine experience for 18F-fluciclovine PET/MRI and three readers with abdominal imaging experience for MRI alone. Findings scored as 2 or 3 by at least two readers of a given modality were considered positive. A single reader measured SUVmean, SUVmax, and volume of the MRI-defined intraprostatic lesion and SUVmax of suspicious lymph nodes on PET before and after initiation of ADT. Changes in SUV were analyzed using nonparametric Wilcox-on signed-rank tests. RESULTS. The biopsy-proven lesion in the prostate gland was accurately identified in all 14 patients on both MRI and 18F-fluciclovine PET/MRI. Suspected nodal metastases were detected in three patients on MRI and seven patients on 18F-fluciclovine PET/MRI. After ADT, all patients showed decreased activity within the intraprostatic lesion and/or all suspicious lymph nodes. The primary lesion SUVmean was 4.5 ± 1.1 (range, 2.7-6.5) before treatment and 2.4 ± 1.1 (range, 0.0-3.6) after initiation of ADT (p = .008). For suspicious lymph nodes, the pretreatment SUVmax was 5.5 ± 3.7 (range, 2.8-12.7) and the post-treatment SUVmax was 2.8 ± 1.4 (range, 1.4-5.5) (p = .03). CONCLUSION.18F-labeled fluciclovine PET/MRI shows potential utility in initial staging of high-risk prostate cancer and in evaluating response to ADT. CLINICAL IMPACT. Given the FDA approval and widespread availability of 18F-fluciclovine, the findings could have an impact in the immediate future in guiding initial management of patients with prostate cancer. TRIAL REGISTRATION. ClinicalTrials.gov NCT03264456.

Primary lymph-node staging with 68Ga-PSMA PET in high-risk prostate cancer: pathologic correlation with extended pelvic lymphadenectomy specimens

Aim of the studyThis study aims to assess the diagnostic efficacy of Gallium-68-prostate-specific membrane antigen positron emission tomography (PET)/computed tomography (CT) (68Ga PSMA PET-CT) in primary nodal staging of high-risk prostate cancer (PCa) when compared to pathologic findings of extended pelvic lymph-node dissection (eLND). Materials and methodsThe records of high-risk PCa patients who were preoperatively staged through 68Ga PSMA PET-CT and who underwent robot-assisted radical prostatectomy with eLND either alone or as part of multimodal definitive therapy between August 2016 and November 2019 were retrospectively reviewed. Surgeons were not blinded to the results of the 68Ga PSMA PET-CT scan. Pathologic uptake was defined as any anomalous uptake which was not better explained by another cause and was suggestive of PCa. The reference standard for this study was the pathologic confirmation using a node-based analysis. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for 68Ga PSMA PET-CT were calculated in a per-patient analysis using IBM SPSS Statistics version 25. ResultsSeventeen patients met the selection criteria. Mean age was 63 years (range 44–77) and mean and median preoperative serum prostate specific antigen was 19.25 and 9 ng/ml (range 6–131), respectively. The most common pathologic Gleason score was 8 (52.9% of cases). Seven patients (41%) had positive surgical margins and were submitted to adjuvant radiotherapy. Mean number of per patient removed lymph-nodes was 13 (±2.19). 68Ga PSMA PET-CT showed findings compatible with lymph node metastases in 4/17 patients and with locally-confined disease in 13/17 patients. Following pathologic confirmation, the per-patient sensibility of the 68Ga PSMA PET-CT was calculated at 75% (1 false negative) and the specificity at 92.3% (1 false positive) for detection of lymph node metastasis on primary staging of high-risk PCa patients. Positive and negative predictive value were 75% and 92.3%, respectively; accuracy of the test was calculated at 88.2%. All patients were submitted to 68Ga PSMA PET-CT re-evaluation 6 months after surgery and tested negative for local, nodal, or distant recurrence of disease. Conclusions68Ga PSMA PET-CT appears to have a high negative predictive value for local lymph node metastases in high-risk primary PCa when compared to pathologic findings of eLND. Its role in the primary nodal staging of high-risk PCa patients worths further evaluation.

Is there a utility of adding skeletal imaging to 68-Ga-prostate-specific membrane antigen-PET/computed tomography in initial staging of patients with high-risk prostate cancer?

Both bone-scan and cross-sectional imaging are indicated in the staging of high-risk prostate cancer (PCa). However, 68Ga-prostate-specific membrane antigen (PSMA)-PET/computed tomography (CT) has proven to be an excellent tracer for detection of skeletal metastases. The aim of this study was to assess if adding skeletal imaging (with 18F-Fluoride-PET/CT) to 68-Ga-PSMA-PET/CT had any impact on high-risk PCa staging. Fifty treatment-naive, histopathologically proven, high-risk (European Association of Urology) PCa patients underwent both 68-Ga-PSMA-PET/CT and 18F-Fluoride-PET/CT for staging. Fluoride-PET/CT detected significantly a higher number of skeletal metastases/patient than PSMA-PET/CT (median 4.5/patient vs 3.0; Wilcoxan-signed-rank-test, P = 0.060) and there was a significantly higher proportion of only Fluoride-avid than only PSMA-avid lesions (McNemar-test P < 0.001). No significant advantage was seen in patient-wise metrics. Most lesions missed by PSMA-PET/CT were in flat bones (25/33). serum prostate specific antigen (S.PSA) showed positive correlation with both, the number of lesions [r(PSMA)-0.555 (P = 0.006) and r(Fluoride)-0.622 (P = 0.001)] as well as tumor to background ratio (TBR) [[r-0.706 (P < 0.001) and 0.516 (P = 0.010)]. Median TBR was significantly higher in PSMA-PET/CT (22.77 vs 16.30; P < 0.001). All three patients with only Fluoride-avid lesions (also not identified in bone-scan) showed biochemical response with additional therapy. Though, Fluoride-PET/CT detected a higher absolute number of lesions than PSMA-PET/CT, no significant advantage was seen in patient-wise metrics. Fluoride-PET/CT added second-line management in only 3/50 patients, which could have been reduced to 1/50, with more sensitive evaluation of flat bones in PSMA-PET-CT. Therefore, additional skeletal imaging is not needed with 68-Ga-PSMA-PET/CT in initial staging of high-risk PCa.

18F-DCFPyL PET/CT for primary staging in 160 high-risk prostate cancer patients; metastasis detection rate, influence on clinical management and preliminary results of treatment efficacy.

Prostate-specific membrane antigen (PSMA) PET/CT shows better diagnostic performance for detection of lymph node and bone metastases as compared to conventional imaging. Studies of PSMA PET/CT in primary staging comprise highly selected patient cohorts. This study evaluates 18F-DCFPyL PET/CT as first-line imaging modality for primary staging of high-risk prostate cancer. From February 2018 until April 2019, all patients with high-risk prostate cancer received 18F-DCFPyL PET/CT for staging of prostate cancer. Baseline characteristics, findings at 18F-DCFPyL PET/CT, number and type of required additional diagnostic procedures, findings at additional diagnostic procedures, and effects of therapy on PSA levels for all patients treated with curative intent were collected and evaluated. One hundred-sixty patients were included in the study of which 90 (56%) had evidence of metastasized disease (N1, M1a, M1b and, M1c in 49%, 28%, 31%, and 3% respectively). Additional diagnostic imaging was needed in 2/160 patients (1%) because of equivocal findings on 18F-DCFPyL PET/CT. Eighty-one patients had evidence of PSMA-positive lymph node metastases, of whom 39 (48%) had no enlarged lymph nodes on CT; 18F-DCFPyL PET detected additional metastatic lymph nodes in 41/42 patients that had evidence of lymph node metastases on CT. 18F-DCFPyL PET altered patients' management in 17% of patients. 18F-DCFPyL PET/CT can be used as first-line imaging modality for therapy selection in patients with primary high-risk prostate cancer, without need for further diagnostic imaging procedures in the majority of patients.