Extent of disease in recurrent prostate cancer determined by [68Ga]PSMA-HBED-CC PET/CT in relation to PSA levels, PSA doubling time and Gleason score

Estimating the Optimal Time to Perform a Positron Emission Tomography With Prostate-Specific Membrane Antigen in Prostatectomized Patients, Based on Data From Clinical Practice

Prostatectomized patients are at risk of resurgence, and for this reason, during a follow-up period, they are monitored for prostate-specific antigen (PSA) growth, an indicator of tumor progression. The presence of tumors can be evaluated with an expensive exam, called positron emission tomography with prostate-specific membrane antigen (PET-PSMA). To justify the high cost of the PET-PSMA and, at the same time, to contain the risk for the patient, this exam should be recommended only when the evidence of tumor progression is strong. With the aim of estimating the optimal time to recommend the exam based on the patient's history and collected data, we build a hierarchical Bayesian model that describes, jointly, the PSA growth curve and the probability of a positive PET-PSMA. With our proposal, we process all past and present information about the patients PSA measurement and PET-PSMA results, in order to give an informed estimate of the optimal time, improving current practice.

Detection Rates of PSMA-PET Radiopharmaceuticals in Recurrent Prostate Cancer: A Systematic Review

Background/Objectives: To conduct a systematic review to evaluate the detection rates (DR) of the three FDA-approved PSMA-targeted radiopharmaceuticals in patients with recurrent prostate cancer. Methods: Two individuals systematically searched MEDLINE, ScienceDirect, and Cochrane Libraries (February 2025), and independently reviewed all results to identify studies reporting patient-level 68Ga-PSMA-11, 18F-DCFPyL, or 18F-flotufolastat DR in ≥100 evaluable patients with recurrent prostate cancer. Sample-weighted means (SWM) of extracted DR were calculated. Results: Of 5059 published articles, 37 met our inclusion criteria, reporting data from 8843 patients undergoing 68Ga-PSMA-11 (n = 27), 18F-DCFPyL (n = 8), or 18F-flotufolastat (n = 2) studies. Heterogeneity was noted across enrolled populations, particularly in prior treatments. 68Ga-PSMA-11 studies recruited patients with marginally higher median PSA than 18F-DCFPyL or 18F-flotufolastat studies (median PSA ranged from 0.1 to 10.7, 0.2-2.5, and 0.6-1.1, respectively). Reported overall DR ranged from 25 to 91% for 68Ga-PSMA-11, 49-86% for 18F-DCFPyL, and 73-83% for 18F-flotufolastat, with SWM of 71%, 66%, and 79%, respectively. Post-prostatectomy DR were reported in 18 articles, resulting in SWM DR of 58% for 68Ga-PSMA-11 (n = 12), 55% for 18F-DCFPyL (n = 4), and 76% for 18F-flotufolastat (n = 2). Among post-radiotherapy patients, SWM were 87% for 68Ga-PSMA-11 (n = 4), 90% for 18F-DCFPyL (n = 2), and 99% for 18F-flotufolastat (n = 1). SWM DR at PSA < 1 ng/mL were 53%, 42%, and 66% for 68Ga-PSMA-11 (n = 13), 18F-DCFPyL (n = 5), and 18F-flotufolastat (n = 2), respectively. Conclusions: Considerable heterogeneity exists across populations in studies of diagnostic PET radiopharmaceuticals. Despite a paucity of 18F-DCFPyL and 18F-flotufolastat studies compared with 68Ga-PSMA-11, the available data suggest that all three radiopharmaceuticals provide high overall DR in patients with biochemical recurrence of prostate cancer.

Comparative diagnostic performance of 68Ga-PSMA-11 PET/CT and 68Ga-PSMA-11 PET/MRI in detecting biochemical recurrent bone metastasis in prostate cancer: a systematic review and meta-analysis

BackgroundThe comparative diagnostic performance of 68Gallium (Ga)-PSMA-11 PET/CT and 68Ga-PSMA-11 PET/MRI in detecting bone metastases in prostate cancer (PCa) remains unclear.PurposeTo systematically evaluate the early detection rate of biochemical recurrent (BCR) bone metastasis in PCa utilizing 68Ga-PSMA-11 PET/CT and 68Ga-PSMA-11 PET/MRI.Material and MethodsWe searched PubMed, Embase, and Web of Science for relevant articles up to April 2023 and extracted studies that examined the positivity rate of both 68Ga-PSMA-11 PET/CT and 68Ga-PSMA-11 PET/MRI in the context of the BCR bone metastasis of PCa patients. Random-effects model was used to compare positivity rates for two imaging modalities. Heterogeneity among studies was assessed using the I2 statistic. To evaluate the methodological quality of studies, we employed Quality Assessment of Diagnostic Performance Studies method. The study protocol was registered in PROSPERO (CRD42023454118).ResultsA total of 1670 publications were originally identified; 58 studies, encompassing a cohort of 8037 patients, met the inclusion criteria. Regarding the evaluation of BCR bone metastasis, results suggest no statistically significant difference in the utilization of 68Ga-PSMA-11 PET/CT versus 68Ga-PSMA-11 PET/MRI in 58 non-head-to-head studies (0.21, 95% CI=0.19-0.24 and 0.17, 95% CI=0.11-0.23; P = 0.19) and four head-to-head studies (0.16, 95% CI=0.08-0.27 and 0.16, 95% CI=0.08-0.27; P = 1.00). Meta-regression showed the study design of influenced the heterogeneity in the PET/MRI group (P < 0.01); but analysis of PET/CT did not identify the potential reason for heterogeneity.ConclusionThere was no statistically significant difference in identifying BCR bone metastasis in PCa patients between 68Ga-PSMA-11 PET/CT and 68Ga-PSMA-11 PET/MRI.

Biology-guided radiotherapy in metastatic prostate cancer: time to push the envelope?

The therapeutic landscape of metastatic prostate cancer has undergone a profound revolution in recent years. In addition to the introduction of novel molecules in the clinics, the field has witnessed a tremendous development of functional imaging modalities adding new biological insights which can ultimately inform tailored treatment strategies, including local therapies. The evolution and rise of Stereotactic Body Radiotherapy (SBRT) have been particularly notable in patients with oligometastatic disease, where it has been demonstrated to be a safe and effective treatment strategy yielding favorable results in terms of disease control and improved oncological outcomes. The possibility of debulking all sites of disease, matched with the ambition of potentially extending this treatment paradigm to polymetastatic patients in the not-too-distant future, makes Biology-guided Radiotherapy (BgRT) an attractive paradigm which can be used in conjunction with systemic therapy in the management of patients with metastatic prostate cancer.

Evaluation of Gallium-68 prostate-specific membrane antigen, positron emission tomography/computed tomography (GA-68 PSMA PET/CT) in recurrent prostate cancer: a retrospective review of initial clinical experience at Tygerberg Hospital

Introduction

prostate cancer recurrence after definitive therapy for organ-confined disease often manifests as rising prostate-specific antigen (PSA) levels without clinically overt disease. 68Gallium prostate-specific membrane antigen, positron emission tomography/computed tomography (68GaPSMA PET/CT) imaging plays a major role in the management of recurrent prostate cancer. The purpose of this study was to assess the positivity rate of 68Ga PSMA PET/CT scans in cases of prostate cancer recurrence, and to compare the results with existing international literature.

Methods

a retrospective analysis of 177 68Ga PSMA PET/CT scans of patients with biochemically proven disease recurrence was performed. The possible association of a positive PSMA PET/CT with the PSA level and Gleason score were analyzed.

Results

a total of 177 68Ga PSMA PET/CT scans were performed in 163 patients (median age 66 years). Of these, 117 (66%) scans detected the site of disease recurrence. Among patients with PSA 0.2-0.99 ng/ml, 23/49 (47%, p<0.0001) were positive, and 20/35 (57%, p<0.0005) were positive in the group of patients with PSA 1.00-1.99. When PSA values were further categorized into PSA <2 ng/ml and PSA ≥2 ng/ml, detection rates were 49% and 86% respectively (p <0.0001). The scans were positive in 65% of patients with Gleason score of <7, 62% with Gleason score of =7 and 68% with Gleason score >7 (p=0.745).

Conclusion

there was an increase in the detection rate with an increase in the PSA. Gleason score was not a predictor of a positive 68Ga PSMA PET/CT scan. 68Ga-PSMA PET/CT should be prioritized in patients with biochemical recurrence with PSA levels >0.2 ng/ml.

A bicentric retrospective study of the correlation of EAU BCR risk groups with 18F-PSMA-1007 PET/CT detection in prostate cancer biochemical recurrence

The European Association of Urology (EAU) has proposed a risk stratification for patients harboring biochemical recurrence (BCR) after radical prostatectomy: ISUP < 4 and PSA doubling time (PSAdt) > 12 months for low risk, and ISUP ≥ 4 or PSAdt ≤ 12 months for high risk. This dual-center retrospective study aims to investigate the correlation between the EAU risk stratification for BCR following radical prostatectomy and the detection rate of lesions using 18F-PSMA-1007 PET/CT. Among the 71 included patients (58 high-risk, 13 low-risk), with a median PSA level of 1.43 ng/ml, PET/CT demonstrated a significantly higher positivity in the high-risk group compared to the low-risk group (72.4% vs. 38.0%, p = 0.026). Analysis of recurrence sites revealed a similar proportion of pelvic-confined disease in both groups (24.1% vs. 23.1%, p = 0.935), but a significantly higher incidence of metastatic disease in the high-risk group (51.7% vs. 15.4%, p = 0.017), with detailed findings indicating an increased prevalence of bone metastases in the high-risk BCR group (37.8% vs. 7.7%, p = 0.048). Therefore, PSMA PET/CT offers valuable insights for treatment decisions, aligning with the evolving landscape of prostate cancer management.

Predicting 18F-DCFPyL-PET/CT Scan Positivity in Prostate Cancer Patients with Biochemical Recurrence

RATIONALE AND OBJECTIVES

To analyze variables that can predict the positivity of 18F-DCFPyL- positron emission tomography/computed tomography (PET/CT) and extent of disease in patients with biochemically recurrent (BCR) prostate cancer after primary local therapy with either radical prostatectomy or radiation therapy.

MATERIALS AND METHODS

This is a retrospective analysis of a prospective single institutional review board-approved study. We included 199 patients with biochemical recurrence and negative conventional imaging after primary local therapies (radical prostatectomy n = 127, radiation therapy n = 72). All patients underwent 18F-DCFPyL-PET/CT. Univariate and multivariate logistic regression analyses were used to determine predictors of a positive scan for both cohort of patients. Regression-based coefficients were used to develop nomograms predicting scan positivity and extra-pelvic disease. Decision curve analysis (DCA) was implemented to quantify nomogram's clinical benefit.

RESULTS

Of the 127 (63%) post-radical prostatectomy patients, 91 patients had positive scans - 61 of those with intrapelvic lesions and 30 with extra-pelvic lesions (i.e., retroperitoneal or distant nodes and/or bone/organ lesions). Of the 72 post-radiation therapy patients, 65 patients had positive scans - 39 of them had intrapelvic lesions and 26 extra-pelvic lesions. In the radical prostatectomy cohort, multivariate regression analysis revealed original International Society of Urological Pathology category, prostate-specific antigen (PSA), prostate-specific antigen doubling time (PSAdt), and time from BCR (mo) to scan were predictors for scan positivity and presence of extra-pelvic disease, with an area under the curve of 80% and 78%, respectively. Positive versus negative tumor margin after radical prostatectomy was not related to scan positivity or to the presence of positive extra-pelvic foci. In the radiation therapy cohort, multivariate regression analysis revealed that PSA, PSAdt, and time to BCR (mo) were predictors of extra-pelvic disease, with area under the curve of 82%. Because only seven patients in the radiation therapy cohort had negative scans, a prediction model for scan positivity could not be analyzed and only the presence of extra-pelvic disease was evaluated.

CONCLUSION

PSA and PSAdt are consistently significant predictors of 18F-DCFPyL PET/CT positivity and extra-pelvic disease in BCR prostate cancer patients. Stratifying the patient population into primary local treatment group enables the use of other variables as predictors, such as time since BCR. This nomogram may guide selection of the most suitable candidates for 18F-DCFPyL-PET/CT imaging.

Updates on Management of Biochemical Recurrent Prostate Cancer

OPINION STATEMENT

Patients with biochemical recurrent prostate cancer (BCR) are a heterogeneous group, whereby a personalized approach to management is critical. Patients with high-risk features such as PSA doubling time (PSADT) ≤ 9-12 months warrant earlier imaging for metastasis detection and consideration for intensified therapy (beyond intermittent androgen deprivation alone) during this phase of BCR-only disease. The BCR phase represents a unique opportunity to impact disease survival and delay metastasis progression. There is compelling evidence from the EMBARK trial that ADT monotherapy is no longer the optimal consideration for high-risk BCR patients.

Prostate Cancer Liver Metastasis: An Ominous Metastatic Site in Need of Distinct Management Strategies

Prostate cancer liver metastasis (PCLM), seen in upwards of 25% of metastatic castration-resistant PC (mCRPC) patients, is the most lethal site of mCRPC with a median overall survival of 10-14 months. Despite its ominous prognosis and anticipated rise in incidence due to longer survival with contemporary therapy, PCLM is understudied. This review aims to summarize the existing literature regarding the risk factors associated with the development of PCLM, and to identify areas warranting further research. A literature search was conducted through Ovid MEDLINE from 2000 to March 2023. Relevant subject headings and text words were used to capture the following concepts: "Prostatic Neoplasms", "Liver Neoplasms", and "Neoplasm Metastasis". Citation searching identified additional manuscripts. Forty-one studies were retained for detailed analysis. The clinical risk factors for visceral/liver metastasis included <70 years, ≥T3 tumor, N1 nodal stage, de novo metastasis, PSA >20 ng/mL, and a Gleason score >8. Additional risk factors comprised elevated serum AST, LDH or ALP, decreased Hb, genetic markers like RB1 and PTEN loss, PIK3CB and MYC amplification, as well as numerous PC treatments either acting directly or indirectly through inducing liver injury. Further research regarding predictive factors, early detection strategies, and targeted therapies for PCLM are critical for improving patient outcomes.

Single-fraction prostate-specific membrane antigen positron emission tomography- and multiparametric magnetic resonance imaging-guided stereotactic body radiotherapy for prostate cancer local recurrences

OBJECTIVE

To analyse the efficacy and safety of focal prostate-specific membrane antigen positron emission tomography (PSMA-PET)- and multiparametric magnetic resonance imaging (mpMRI)-guided single-fraction stereotactic body radiotherapy (SBRT) for the treatment of prostate cancer (PCa) local recurrences.

PATIENTS AND METHODS

Patients with PSMA-PET-positive PCa local recurrences treated with single-fraction SBRT between 2016 and 2020 were included. Identification for subsequent recurrences or metastatic spread based on increasing prostate-specific antigen (PSA) levels were evaluated using PSMA-PET imaging.

RESULTS

A total of 64 patients were identified. Patients received various treatments before SBRT (31 patients with radical prostatectomy [RP], 18 external beam radiotherapy [EBRT] with RP, five EBRT, and the remaining 10 other combinations). The median follow-up was 21.6 months. The median PSA level before SBRT was 1.47 ng/mL. All patients received a single-fraction treatment with a median prescription dose and isodose line of 21 Gy and 65%, respectively. At the time of SBRT, six patients (9%) received an androgen deprivation therapy (ADT). PSA levels decreased after SBRT (P = 0.03) and three local recurrences were detected during the follow-up. The progression-free survival after 1-, 2-, and 3-years was 85.3%, 65.9%, and 51.2%, respectively. Six patients (9%) started ADT after SBRT due to disease progression. The rates of newly started ADT after 1-, 2-, and 3-years were 1.8%, 7.3%, and 22.7%, respectively. Grade 1 or 2 toxicities occurred in six patients (9%); no high-grade toxicity was observed.

CONCLUSION

While the available data for SBRT in the PCa local recurrence setting describe outcomes for fractionated irradiations, the findings of this first analysis of single-fraction, PSMA-PET- and mpMRI-guided focal SBRT are encouraging. Such treatment appears to be a safe, efficient, and time-saving therapy even in intensively pretreated patients. Recurrence-directed treatments can delay the use of ADT and could avoid prostate bed irradiation in selected patients.

PSMA-11 PET/CT for Detection of Recurrent Prostate Cancer in Patients With Negative Choline PET/CT

INTRODUCTION

Prostate adenocarcinoma (CaP) is the leading cancer in men. After curative treatment, from 27% to 53% of patients will experience biochemical recurrence (BR). With the development of focal therapies, precise early identification of recurrence's sites is of utmost importance in order to deliver individualized treatment on positive lesions. The aim of this study was to assess the detection rate (DR) of ⁶⁸Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) in selected patients with prostate cancer BR and recent negative ¹⁸F-choline PET/CT.

PATIENTS AND METHODS

We performed a retrospective analysis including all patients with CaP referred for BR with a negative ¹⁸F-choline PET/CT, and who underwent ⁶⁸Ga-PSMA-11 PET/CT between October, 2018 and December, 2019. The overall DR of ⁶⁸Ga-PSMA-11 PET/CT was calculated, and described according to BR characteristics especially PSA levels and velocity. Patients were followed up for at least 1 year. Patient management following ⁶⁸Ga-PSMA-11 PET/CT and PSA levels evolution after treatment were also recorded.

RESULTS

One hundred fifty-nine patients comprising 164 examinations were analyzed. The overall DR of ⁶⁸Ga-PSMA-11 PET/CT for BR was 65.9% (95CI, 58.6-73.1). The DR was 52.5% (95CI, 39.9-65.0), 70.6% (95CI, 55.3-85.9), 70.4% (95CI, 53.1-87.6), and 78.6% (95CI, 66.2-91.0) for PSA levels between 0.2 and 0.49 ng/mL, 0.5 to 0.99 ng/mL, 1 to 1.99 ng/mL and PSA ≥ 2 ng/mL, respectively. The DR was 70.7% (95CI, 59.0-82.4) with a PSA doubling time (PSA-DT) ≤6 months and 65.2% (95CI, 55.5-74.9) with a PSA-DT >6 months. Around 3/4 of patients (75.9%) with a positive ⁶⁸Ga-PSMA-11 PET/CT initiated treatment, including surgery (2.4%), stereotactic radiotherapy ± androgen deprivation therapy (ADT) (22%) or external conformational radiotherapy ± ADT (46.3%). Patient management changed in 43 cases (39.8%).

CONCLUSION

Our study confirmed the ability of ⁶⁸Ga-PSMA-11 PET/CT to detect occult biochemical recurrence, even in a selected population of CaP patients with negative ¹⁸F-choline PET/CT, even at low PSA levels.

68Ga-PSMA PET/CT in early relapsed prostate cancer patients after radical therapy

Biochemical recurrence (BCR) of prostate cancer (PCa) occurs in about 25% of patients treated with radical prostatectomy (RP) and up to 45% in patients who receive external beam radiotherapy (RT). Early diagnosis of PCa recurrence is of high importance for successful salvage therapy. The aim of the present study is to analyze the efficacy of ⁶⁸ Ga-PSMA PET/CT in detecting the presence of local and/or systemic disease in patients with a history of PCa who have BCR. A total of 52 PCa patients with BCR referred for ⁶⁸ Ga-PSMA PET/CT were recruited from the American University of Beirut Medical Center between November 2017 and December 2019. We compared the performance of PSMA PET/CT to the results and clinical factors based on follow up: PSA, PSA kinetics, primary treatment, and Gleason score. The relationship between the PET/CT findings and clinical indicators of disease were assessed by univariate and multivariate logistic regression. From a total of 52 patients, 34 (65.4%) had positive PSMA-PET/CT scans. Among those, 8/34 (23.5%) received primary RT. For all patients with a positive PSMA-PET: the detection rate was 2/4 (50%) for PSA < 0.2, 5/10 (50%) for PSA 0.2-0.49, 3/6 (50%) for PSA 0.5-0.99, 6/12 (50%) for PSA 1-1.99, 8/9 (88.9%) for PSA 2-3.99, and 10/11 (90.9%) for PSA 4-10.PSMA-PET/CT positivity was significantly associated with PSA level at time of PET scan, PSA doubling time, Gleason score and TNM staging. However, it did not show a significant correlation with radiotherapy as primary treatment, ongoing androgen deprivation therapy (ADT), time to relapse, and initial PSA before therapy. In our single center prospective trial, ⁶⁸ Ga-PSMA PET/CT successfully detected the recurrence of PCa in patients with BCR. Scan positivity was significantly associated with PSA level at time of PET scan, PSA doubling time, Gleason score, and TNM staging. PSMA- PET/CT is a highly promising modality in the work up of patients with PCa in the setting of BCR for earlier detection of disease recurrence.

Comparing the diagnostic performance of radiotracers in prostate cancer biochemical recurrence: a systematic review and meta-analysis

OBJECTIVES

To systematically assess the early detection rate of biochemical prostate cancer recurrence using choline, fluciclovine, and PSMA.

METHODS

Under the guidance of the Preferred Reporting Items for Systematic reviews and Meta-Analysis Diagnostic Test Accuracy guidelines, literature that assessed the detection rates (DRs) of choline, fluciclovine, and PSMA in prostate cancer biochemical recurrence was searched in PubMed and EMBASE databases for our systematic review from 2012 to July 15, 2021. In addition, the PSA-stratified performance of detection positivity was obtained to assess the DRs for various methods, including fluciclovine, PSMA, or choline PET/CT, with respect to biochemical recurrence based on different PSA levels.

RESULTS

In total, 64 studies involving 11,173 patients met the inclusion criteria. Of the studies, 12, 7, and 48 focused on choline, fluciclovine, and PSMA, respectively. The pooled DRs were 24%, 37%, and 44%, respectively, for a PSA level less than 0.5 ng/mL (p < 0.001); 36%, 44%, and 60% for a PSA level of 0.5-0.99 ng/mL (p < 0.001); and 50%, 61%, and 80% for a PSA level of 1.0-1.99 ng/mL (p < 0.001). The DR with 18F-labeled PSMA was higher than that with 68Ga-labeled PSMA, and the DR was 58%, 72%, and 88% for PSA levels < 0.5 ng/mL, 0.5-0.9 ng/mL, and 1.0-1.99 ng/mL, respectively.

CONCLUSION

The DRs of PSMA-radiotracers were greater than those of choline-radiotracers and fluciclovine-radiotracers at the patient level. 18F-labeled PSMA achieved a higher DR than 68Ga-labeled PSMA.

KEY POINTS

• The DRs of PSMA-radiotracers were greater than those of choline-radiotracers and fluciclovine-radiotracers at the patient level. • 18F-labeled PSMA achieved a higher DR than 68Ga-labeled PSMA.

Development and validation of a nomogram for predicting the likelihood of metastasis in prostate cancer patients undergoing Ga-68 PSMA PET/CT due to biochemical recurrence

OBJECTIVE

To develop a nomogram based on commonly used clinical data for predicting the likelihood of metastasis in gallium-68 prostate-specific membrane antigen PET/computed tomography (Ga-68 PSMA PET/CT) scans of prostate cancer patients with confirmed biochemical recurrence (BCR).

METHODS

One-hundred thirty-five ( n  = 135) patients who underwent Ga-68 PSMA PET/CT due to BCR were included in the study. Predictors of metastasis in Ga-68 PSMA PET/CT were determined with multivariable logistic regression analysis. Coefficients derived from the regression model were used to develop a prediction nomogram. The performance of the prediction model was evaluated with receiver operating characteristic analysis. Internal validation was performed with 50 bootstrap resamples, and the nomogram's clinical benefit was assessed with decision curve analysis.

RESULTS

Multivariable logistic regression analysis revealed that ISUP group, prostate-specific antigen (PSA) before PET and PSA doubling time were independent predictors of metastasis in Ga-68 PSMA PET/CT. A prediction nomogram was developed according to this model [the area under curve: 0.866; 95% confidence interval (CI), 0.788-0.944]. The best cutoff value of the nomogram-derived likelihood for predicting metastasis was 60%, with a bootstrap-corrected accuracy of 78.8%. An online version of the nomogram was implemented on pro-gram.nzm.co ( https://pro-gram.nzm.co ).

CONCLUSION

The proposed nomogram provides a practical approach for predicting the likelihood of imaging-based metastasis according to Ga-68 PSMA PET/CT in patients with BCR, with results ≥60% being the most accurate cutoff for referring patients to Ga-68 PSMA PET/CT. If validated in a larger cohort, this tool can serve as a guide for the appropriate use of Ga-68 PSMA PET/CT.

Predictors of Bone Metastases at 68Ga-PSMA-11 PET/CT in Hormone-Sensitive Prostate Cancer (HSPC) Patients with Early Biochemical Recurrence or Persistence

Prostate-specific-membrane-antigen/positron-emission-tomography (PSMA-PET) can accurately detect disease localizations in prostate cancer (PCa) patients with early biochemical recurrence/persistence (BCR/BCP), allowing for more personalized image-guided treatments in oligometastatic patients with major impact in the case of bone metastases (BM). Therefore, this study aimed to identify predictors of BM at PSMA-PET in early-BCR/BCP hormone-sensitive PCa (HSPC) patients, previously treated with radical intent (radiotherapy or radical prostatectomy ± salvage-radiotherapy (SRT)). A retrospective analysis was performed on 443 ⁶⁸Ga-PSMA-11-PET/CT scans. The cohort median PSA at PET-scan was 0.60 (IQR: 0.38–1.04) ng/mL. PSMA-PET detection rate was 42.0% (186/443), and distant lesions (M1a/b/c) were found in 17.6% (78/443) of cases. BM (M1b) were present in 9.9% (44/443) of cases, with 70.5% (31/44) showing oligometastatic spread (≤3 PSMA-positive lesions). In the multivariate binary logistic regression model (accuracy: 71.2%, Nagelkerke-R²: 13%), T stage ≥ 3a (OR: 2.52; 95% CI: 1.13–5.60; p = 0.024), clinical setting (previous SRT vs. first-time BCR OR: 2.90; 95% CI: 1.32–6.35; p = 0.008), and PSAdt (OR: 0.93; 95% CI: 0.88–0.99; p = 0.026) were proven to be significant predictors of bone metastases, with a 7% risk increment for each single-unit decrement of PSAdt. These predictors could be used to further refine the indication for PSMA-PET in early BCR/BCP HSPC patients, leading to higher detection rates of bone disease and more personalized treatments.

The Diagnostic Performance of 18F-PSMA-1007 PET/CT in Prostate Cancer Patients with Early Recurrence after Definitive Therapy with a PSA <10 ng/ml

AIM

The prostate bed is one of the common sites of early recurrence of prostate cancer. The currently used PSMA ligands (⁶⁸Ga-PSMA-11 and ^99mTc-PSMA) undergo early urinary clearance resulting in interfering physiological activity within and surrounding the prostate. This can result in sites of cancer recurrence being obscured. ¹⁸F-PSMA-1007 has an advantage of delayed urinary clearance thus the prostate region is reviewed without any interfering physiological activity. The aim of this study was to determine the diagnostic performance of ¹⁸F-PSMA-1007 PET/CT in patients with early biochemical recurrence after definitive therapy.

METHODS

Forty-six Prostate cancer (mean age 66.7±7.5, range 48-87 years) presenting with biochemical recurrence (median PSA 1.6ng/ml, range 0.1-10.0) underwent non-contrast-enhanced ¹⁸F-PSMA-1007 PET/CT. PET/CT findings were evaluated qualitatively and semiquantitatively (SUVmax) and compared to the results of histology, Gleason grade, and conventional imaging.

RESULTS

Twenty-four of the 46 (52.2%) patients demonstrated a site of recurrence on ¹⁸F-PSMA-1007 PET/CT. Oligometastatic disease was detected in 15 (32.6%) of these patients. Of these 10 (37.5%) demonstrated intra-prostatic recurrence, lymph node disease was noted in 11 (45.8%) whilst two patients demonstrated skeletal metastases. The detection rates for PSA levels 0-<0.5, 0.5-<1, 1-2, >2 were 31.3%, 33.3%, 55.6% and 72.2% respectively. 7 (29.2%) of the positive patients had been described as negative or equivocal on conventional imaging. An optimal PSA cut-off level of 1.3ng/ml was found.

CONCLUSION

¹⁸F-PSMA-1007 demonstrated good diagnostic performance detecting sites of recurrence. Its ability to detect sites of recurrence in the setting of early biochemical recurrence will have a significant impact on patient management.

Oligometastatic disease in biochemical recurrence of prostate cancer: Prevalence on PSMA PET/CT and consecutive metastasis-directed therapy - Experience at a tertiary referral center

AIM

The aim of our study was to address the prevalence of oligometastatic recurrent prostate cancer (PCa) on PSMA-PET and the associated practice of metastasis-directed therapy (MDT). Next, we aimed to determine a PSA threshold below which most patients had local and/or oligometastatic recurrence on PSMA-PET.

METHODS

One hundred and ten consecutive patients with biochemical recurrence (BCR) after radical prostatectomy (RP) ± radiation were referred for ⁶⁸Ga-PSMA-11 or ¹⁸F-DCFPyL PET/CT. We correlated the location and number of PSMA-positive lesions against the treatment choice after imaging. Detection rates were stratified by PSA levels at the time of PET/CT. The study design was monocentric retrospective.

RESULTS

Thirty-four patients (30.9%) had a PSMA-negative scan, while 17 (15.5%) had local recurrence and 59 (53.6%) had metastatic recurrence on PSMA-PET. ROC analysis revealed a cut-off of ≤3 metastatic lesions on PSMA-PET for the steering of treatment decisions towards MDT rather than solely systemic therapy (AUC: 0.88). Defined as 3 or fewer metastatic lesions, oligometastatic recurrent PCa was found in up to 30% (33/110) of all patients. At PSA levels below 3.5 ng/ml, the rate of PSMA-positive disease that was locally confined or oligometastatic was 76% (45/59), dropping significantly to 29.4% (5/17) above this threshold (p<0.001) as polymetastatic findings became more frequent.

CONCLUSION

The detection of ≤3 oligometastases on PSMA-PET encouraged the consecutive pursuit of MDT instead of systemic therapy alone. PSMA-PET predominantly captured patients at recurrence stages amenable to localized treatment when initiated at PSA levels below 3.5 ng/ml.

Evaluation of machine learning strategies for imaging confirmed prostate cancer recurrence prediction on electronic health records

BACKGROUND

The main screening parameter to monitor prostate cancer recurrence (PCR) after primary treatment is the serum concentration of prostate-specific antigen (PSA). In recent years, Ga-68-PSMA PET/CT has become an important method for additional diagnostics in patients with biochemical recurrence.

PURPOSE

While Ga-68-PSMA PET/CT performs better, it is an expensive, invasive, and time-consuming examination. Therefore, in this study, we aim to employ modern multivariate Machine Learning (ML) methods on electronic health records (EHR) of prostate cancer patients to improve the prediction of imaging confirmed PCR (IPCR).

METHODS

We retrospectively analyzed the clinical information of 272 patients, who were examined using Ga-68-PSMA PET/CT. The PSA values ranged from 0 ng/mL to 2270.38 ng/mL with a median PSA level at 1.79 ng/mL. We performed a descriptive analysis using Logistic Regression. Additionally, we evaluated the predictive performance of Logistic Regression, Support Vector Machine, Gradient Boosting, and Random Forest. Finally, we assessed the importance of all features using Ensemble Feature Selection (EFS).

RESULTS

The descriptive analysis found significant associations between IPCR and logarithmic PSA values as well as between IPCR and performed hormonal therapy. Our models were able to predict IPCR with an AUC score of 0.78 ± 0.13 (mean ± standard deviation) and a sensitivity of 0.997 ± 0.01. Features such as PSA, PSA doubling time, PSA velocity, hormonal therapy, radiation treatment, and injected activity show high importance for IPCR prediction using EFS.

CONCLUSION

This study demonstrates the potential of employing a multitude of parameters into multivariate ML models to improve identification of non-recurring patients compared to the current focus on the main screening parameter (PSA). We showed that ML models are able to predict IPCR, detectable by Ga-68-PSMA PET/CT, and thereby pave the way for optimized early imaging and treatment.

Prostate-specific membrane antigen (PSMA) fusion imaging in prostate cancer: PET-CT vs PET-MRI

OBJECTIVES

To investigate whether PET-CT or PET-MRI is more appropriate for imaging prostate cancer, in terms of primary tumor detection, local staging and recurrence, as well as lymph nodes and distant metastases.

METHODS

A systematic literature search was conducted on Embase, PubMed/MEDLINE, and the Cochrane Library database. Studies evaluating the diagnostic performance of PET-CT vs PET-MRI in prostate cancer patients were emphasized.

RESULTS

We reviewed 57 original research articles during the period 2016-2021: 14 articles regarding the radiotracer PSMA; 18 articles regarding the primary tumor detection, local tumor staging, managing local recurrence; 17 articles for managing lymph node metastases; and eight articles for managing bone and other distant metastases. PSMA PET could be complementary to mpMRI for primary prostate cancer localization and is particularly valuable for PI-RADS three lesions. PET-MRI is better than PET-CT in local tumor staging due to its specific benefit in predicting extracapsular extension in MRI-occult prostate cancer patients. PET-MRI is likely superior as compared with PET-CT in detecting local recurrence, and has slightly higher detection rates than PET-CT in lymph node recurrence. PET-CT and PET-MRI seem to have equivalent performance in detecting distant bony or visceral metastases.

CONCLUSION

In conclusion, PET-MRI is suitable for local and regional disease, either primary staging or restaging, whereas PET-CT is valuable for managing distant bony or visceral metastasis.

ADVANCES IN KNOWLEDGE

We reviewed the emerging applications of PET-MRI and PET-CT in clinical aspects. Readers will gain an objective overview on the strength and shortfalls of PET-MRI or PET-CT in the management of prostate cancer.

The Value of Multimodality PET/CT Imaging in Detecting Prostate Cancer Biochemical Recurrence

Prostate cancer (PCa) induced death is the predominant cause of cancer-related death among men in 48 countries. After radical treatment, biochemical recurrence has become an important factor for prognosis. The early detection and diagnosis of recurrent lesions are very helpful in guiding treatment and improving the prognosis. PET/CT is a promising method for early detection of lesions in patients with biochemical recurrence of prostate cancer. This article reviews the progress of the research on PET/CT in the PCa biochemical recurrence and aims to introduce new technologies and provide more direction for future research.

Pilot study comparing dominant intraprostatic lesion volume using Ga-68 prostate-specific membrane antigen PET-computed tomography and multiparametric MRI

PURPOSE

The standard imaging used for delineation of dominant intraprostatic lesion (DIL) is multiparametric MRI (mpMRI). The use of biologic imaging such as Ga-68 prostate-specific membrane antigen (PSMA) PET-computed tomography (PET-CT) for this purpose is being explored in view of increased sensitivity of this modality and the associated ease of delineation.

MATERIALS AND METHODS

The primary objective of the study was to compare the autogenerated volumes of the DIL in Ga-68 PSMA PET-CT with the standard volume delineated in mpMRI. Twenty patients with biopsy-proven untreated prostatic adenocarcinoma were included. Multiple percentages of the maximum standardized uptake value (%SUVmax) were used to autogenerate DIL volumes in Ga-68 PSMA PET-CT and these volumes were numerically matched with the consensus DIL volume in mpMRI. PSMA tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were also calculated for each lesion.

RESULTS

Median volume of DIL in mpMRI was 4 cm (interquartile range, IQR = 2.5-7.6 cm). The IQR for interobserver variability was 0.5-2.5 cm. Median SUVmax of the DIL was 14.1 (IQR = 10.2-22.3). Median %SUVmax corresponding to mpMRI volume was 41% of SUVmax (IQR = 34-55%). There was a strong negative correlation between MRI volume and %SUVmax (r = -0.829, P < 0.001). There was a significant correlation between TL-PSMA and prostate-specific antigen (r = 0.609, P = 0.004).

CONCLUSIONS

The median DIL volume was 4 cm and median %SUVmax corresponding to MR volume of DIL was 41%. A strong inverse relationship is found between mpMRI-defined DIL volume and the %SUVmax which generates similar volume in Ga-68 PSMA PET-CT. TL-PSMA could be a quantitative biomarker for tumor load and prognosis.

The role of lymph node dissection in salvage radical prostatectomy for patients with radiation recurrent prostate cancer

PURPOSE

To examine the effect of lymph node dissection on the outcomes of patients who underwent salvage radical prostatectomy (SRP).

MATERIAL AND METHODS

We retrospectively reviewed data from radiation-recurrent patients with prostate cancer (PCa) who underwent SRP from 2000-2016. None of the patients had clinical lymph node involvement before SRP. The effect of the number of removed lymph nodes (RLNs) and the number of positive lymph nodes (PLNs) on biochemical recurrence (BCR)-free survival, metastases free survival, and overall survival (OS) was tested in multivariable Cox regression analyses.

RESULTS

About 334 patients underwent SRP and pelvic lymph node dissection (PLND). Lymph node involvement was associated with increased risk of BCR (p < .001), metastasis (p < .001), and overall mortality (p = .006). In a multivariable Cox regression analysis, an increased number of RLNs significantly lowered the risk of BCR (hazard ratio [HR] 0.96, p = .01). In patients with positive lymph nodes, a higher number of RLNs and a lower number of PLNs were associated with improved freedom from BCR (HR 0.89, p = .001 and HR 1.34, p = .008, respectively). At a median follow-up of 23.9 months (interquartile range, 4.7-37.7), neither the number of RLNs nor the number of PLNs were associated with OS (p = .69 and p = .34, respectively).

CONCLUSION

Pathologic lymph node involvement increased the risk of BCR, metastasis and overall mortality in radiation-recurrent PCa patients undergoing SRP. The risk of BCR decreased steadily with a higher number of RLNs during SRP. Further research is needed to support this conclusion and develop a precise therapeutic adjuvant strategy based on the number of RLNs and PLNs.

Diagnostic performance and clinical impact of 68Ga-PSMA-11 imaging in early relapsed prostate cancer after radical therapy: a prospective multicenter study (IAEA-PSMA study)

Biochemical recurrence (BCR) is a clinical challenge in prostate cancer (PCa) patients, as recurrence localization guides subsequent therapies. The use of PET with prostate-specific membrane antigen (PSMA) provides better accuracy than conventional imaging practice. This prospective, multicenter, international study was performed to evaluate the diagnostic performance and clinical impact of PSMA PET/CT for evaluating BCR in PCa patients in a worldwide scenario. Methods: Patients were recruited from 17 centers in 15 countries. Inclusion criteria were histopathologically proven prostate adenocarcinoma, previous primary treatment, clinically established BCR, and negative conventional imaging (CT plus bone scintigraphy) and MRI results for patients with PSA levels of 4–10 ng/mL. All patients underwent PET/CT scanning with ⁶⁸Ga-PSMA-11. Images and data were centrally reviewed. Multivariate logistic regression analysis was applied to identify the independent predictors of PSMA-positive results. Variables were selected for this regression model on the basis of significant associations in the univariate analysis and previous clinical knowledge: Gleason score, the PSA level at the time of the PET scan, PSA doubling time, and primary treatment strategy. All patients were monitored for a minimum of 6 mo. Results: From a total of 1,004 patients, 77.7% were treated initially with radical prostatectomy and 22.3% were treated with radiotherapy. Overall, 65.1% had positive PSMA PET/CT results. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment (P < 0.001). Treatment was modified on the basis of PSMA PET/CT results in 56.8% of patients. PSMA PET/CT positivity rates were consistent and not statistically different among countries with different incomes. Conclusion: This multicenter, international, prospective trial of PSMA PET/CT confirmed its capability for detecting local and metastatic recurrence in most PCa patients in the setting of BCR. PSMA PET/CT positivity was correlated with the Gleason score, PSA level at the time of the PET scan, PSA doubling time, and radiotherapy as the primary treatment. PSMA PET/CT results led to changes in therapeutic management in more than half of the cohort. The study demonstrated the reliability and worldwide feasibility of PSMA PET/CT in the workup of PCa patients with BCR.

Review of commonly used prostate specific PET tracers used in prostate cancer imaging in current clinical practice

¹⁸F-Fluorodeoxyglucose positron emission tomography (FDG-PET) underperforms in detecting prostate cancer (PCa) due to inherent characteristics of primary and metastatic tumors, including relatively low rate of glucose utilization. Consequently, alternate PCa PET imaging agents targeting other aspects of PCa cell biology have been developed for clinical practice. The most common dedicated PET imaging tracers include ⁶⁸Ga/¹⁸F prostate-specific membrane antigen (PSMA), ¹¹C-Choline, and ¹⁸F-fluciclovine (Axumin™). This review will describe how these agents target specific inherent characteristics of PCa and explore the current literature for these agents for both primary and recurrent PCa, comparing the advantages and limitations of each tracer. Both ¹¹C-Choline and ¹⁸F-Fluciclovine PET have been shown to detect nodal and osseous disease at higher rates compared to FDG-PET but offer no additional benefit in detecting prostate disease, especially in primary staging. As a result, PSMA PET, specifically ⁶⁸Ga-PSMA-11, has emerged as a key imaging option for both primary and recurrent cancer. PSMA PET may be more sensitive than MRI at the local level and more sensitive than ¹¹C-Choline and ¹⁸F-Fluciclovine PET for distant disease. Furthermore, compared to ¹¹C-Choline and ¹⁸F-Fluciclovine PET, ⁶⁸Ga-PSMA-11 PET has higher detection rates at low PSA levels (<2 ng/dL). With improved delineation of disease, PSMA imaging has influenced treatment planning; radiation fields can be narrowed, and patients with isolated or oligo-metastatic disease can be spared systemic therapy. The retrospective nature of many of the studies describing these PCa imaging modalities complicates their assessment and comparison.

Parameters predicting [18F]PSMA-1007 scan positivity and type and number of detected lesions in patients with biochemical recurrence of prostate cancer

BACKGROUND

Detection of the site of recurrence using PSMA-PET/CT is important to guide treatment in patients with biochemical recurrence of prostate cancer (PCa). The aim of this study was to evaluate the positivity rate of [¹⁸F]PSMA-1007-PET/CT in patients with biochemically recurrent PCa and identify parameters that predict scan positivity as well as the type and number of detected lesions. This monocentric retrospective study included 137 PCa patients with biochemical recurrence who underwent one or more [¹⁸F]PSMA-1007-PET/CT scans between August 2018 and June 2019. PET-positive malignant lesions were classified as local recurrence, lymph node (LN), bone or soft tissue lesions. The association between biochemical/paraclinical parameters, as PSA value, PSA doubling time, PSA velocity, Gleason score (GS) and androgen deprivation therapy (ADT), and scan positivity as well as type and number of detected lesions was evaluated using logistic regression analysis (binary outcomes) and Poisson models (count-type outcomes).

RESULTS

We included 175 [¹⁸F]PSMA-1007-PET/CT scans after radical prostatectomy (78%), external beam radiation therapy (8.8%), ADT (7.3%), brachytherapy (5.1%) and high intensity focused ultrasound (0.7%) as primary treatment (median PSA value 1.6 ng/ml). Positivity rate was 80%. PSA value and PSA velocity were significant predictors of scan positivity as well as of the presence of bone and soft tissue lesions and number of bone, LN and soft tissue lesions, both in uni- and/or multivariable analysis. Multivariable analysis also showed prior ADT as predictor of bone and soft tissue lesions, GS as predictor of the number of bone lesions and ongoing ADT as predictor of the number of LN lesions.

CONCLUSION

[¹⁸F]PSMA-1007-PET/CT showed a high positivity rate in patients with biochemically recurrent PCa. PSA value and PSA velocity were significant predictors of scan positivity as well as of the presence and number of bone and soft tissue lesions and the number of LN lesions. Our findings can guide clinicians in optimal patient selection for [¹⁸F]PSMA-1007-PET/CT and support further research leading to the development of a prediction nomogram.

68Ga-Prostate-specific membrane antigen (psma) positron emission tomography (pet) in prostate cancer: a systematic review and meta-analysis

Introduction:

Prostate cancer (PC) is the second most commonly diagnosed cancer in males. ⁶⁸Ga-PSMA PET/CT, a non-invasive diagnostic tool to evaluate PC with prostate-specific membrane antigen (PSMA) expression, has emerged as a more accurate alternative to assess disease staging. We aimed to identify predictors of positive ⁶⁸Ga-PSMA PET and the accuracy of this technique.

Materials and methods:

Diagnostic accuracy cross-sectional study with prospective and retrospective approaches. We performed a comprehensive literature search on PubMed, Cochrane Library, and Embase database in search of studies including PC patients submitted to radical prostatectomy or radiotherapy with curative intent and presented biochemical recurrence following ASTRO 1996 criteria. A total of 35 studies involving 3910 patients submitted to 68-Ga-PSMA PET were included and independently assessed by two authors: 8 studies on diagnosis, four on staging, and 23 studies on restaging purposes. The significance level was α=0.05.

Results:

pooled sensitivity and specificity were 0.90 (0.86-0.93) and 0.90 (0.82-0.96), respectively, for diagnostic purposes; as for staging, pooled sensitivity and specificity were 0.93 (0.86-0.98) and 0.96 (0.92-0.99), respectively. In the restaging scenario, pooled sensitivity and specificity were 0.76 (0.74-0.78) and 0.45 (0.27-0.58), respectively, considering the identification of prostate cancer in each described situation. We also obtained specificity and sensitivity results for PSA subdivisions.

Conclusion:

⁶⁸Ga-PSMA PET provides higher sensitivity and specificity than traditional imaging for prostate cancer.

Feasibility and Oncologic Outcome of Salvage Surgery in Isolated Seminal Vesicle Remnants after Radical Prostatectomy

BACKGROUND

To demonstrate the feasibility of resecting isolated locally relapsing seminal vesicle remnants after primary radical prostatectomy and radiotherapy. Early oncologic outcomes and prognostic risk factors for relapse are demonstrated.

OBJECTIVES AND METHODS

A total of 32 patients underwent open resection of locoregional prostate cancer recurrence in seminal vesicles, as documented on either MRI, 11C-choline, or 68Ga-PSMA PET/CT scans. Age, PSA-DT, PSA, and time to recurrence after primary treatment resection status were used in a uni- and multivariate Cox regression analysis for biochemical relapse after surgery.

RESULTS

Median patient age at time of salvage surgery was 70 (57-77) years. Median PSA and PSA-DT was 2.79 (0.4-61.54) ng/mL and 5.4 (1.6-20.1) months, respectively. Median surgical time and hospital stay was 132 (75-313) min and 5.5 (4-13) days, respectively. After a mean follow-up of 29 (2-92) months, 3 patients died at 8, 14, and 40 months after salvage surgery, and 6 (18.75%) patients remain without biochemical relapse and further treatment. Median progression-free survival was 12 (1-81) months. In the univariable Cox regression analysis, age at time of surgery, preoperative PSA, and the time from primary treatment to salvage surgery were identified as significant parameters for biochemical relapse. Only the interval from primary to salvage surgery was significant in the multivariate analysis with a hazard ratio of 1.008 (95% CI: 1.001-1.015, p = 0.018). In the entire cohort, 4 adjunctive surgeries (3 ureteroneocystostomies and 1 nephrectomy) were needed due to local progressive disease.

CONCLUSION

Seminal vesicle resection is feasible with no significant intra- or postoperative complications. Almost all patients progressed to biochemical or systemic relapse. Salvage surgery must be seen as a preventive for local symptoms, in our experience most often postrenal ipsilateral obstruction.

68Ga-PSMA PET/CT for Patients with PSA Relapse after Radical Prostatectomy or External Beam Radiotherapy

The study aimed to summarize clinical characteristics associated with Gallium-68-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (⁶⁸Ga-PSMA PET/CT) scans as patients were restaged for prostate-specific antigen (PSA) relapse after radical prostatectomy (RP) or external beam radiotherapy (EBRT). Our analyses included multiple cox regression analyses. The study evaluated 95 patients with rising values of PSAs after RP and after EBRT. Sixty 63% of patients had a positive ⁶⁸Ga-PSMA PET/CT scan. Twelve patients (13%) had a positive site in the prostate bed, 29 patients (30%) had a positive site in the regional lymph nodes, and 19 (20%) had positive sites in distant organs. After four years follow-up, 21 patients (22%) died. Using multiple Cox regression analyses, the number of positive sites on the ⁶⁸Ga-PSMA PET/CT scan significantly predicted overall survival (OS) (p = 0.0001), whereas risk score and regional locations of the positive sites were not significant in the multiple Cox regression analyses. Our study indicates that the specific findings of ⁶⁸Ga-PSMA PET/CT scans are important because detailed findings of the scans predict the outcome after salvage treatment of patients with PSA relapse examined with ⁶⁸Ga-PSMA PET/CT scans.

Restaging the Biochemical Recurrence of Prostate Cancer with [68Ga]Ga-PSMA-11 PET/CT: Diagnostic Performance and Impact on Patient Disease Management

Simple Summary

We aimed to evaluate the diagnostic performance, impact on patient disease management, and therapy efficacy prediction of [⁶⁸Ga]Ga-PSMA-11 PET/CT on 294 patients with biochemical recurrence of prostate cancer. We established a composite standard of truth for the imaging based on all clinical data available collected during the follow-up period with a median duration of follow-up of 17 months. Using this methodology, we found that the overall per-patient sensitivity and specificity were both 70%, the patient disease management was changed in 68% of patients, and that [⁶⁸Ga]Ga-PSMA-11 PET/CT impacted this change in 86% of patients. The treatment carried out on the patient was considered effective in 78% of patients; in 89% of patients when guided by [⁶⁸Ga]Ga-PSMA-11 PET/CT versus 61% of patients when not guided by [⁶⁸Ga]Ga-PSMA-11 PET/CT.

Abstract

Background: Detection rates of [⁶⁸Ga]Ga-PSMA-11 PET/CT on the restaging of prostate cancer (PCa) patients presenting with biochemical recurrence (BCR) have been well documented, but its performance and impact on patient management have not been evaluated as extensively. Methods: Retrospective analysis of PCa patients presenting with BCR and referred for [⁶⁸Ga]Ga-PSMA-11 PET/CT. Pathological foci were classified according to six anatomical sites and evaluated with a three-point scale according to the uptake intensity. The impact of [⁶⁸Ga]Ga-PSMA-11 PET/CT was defined as any change in management that was triggered by [⁶⁸Ga]Ga-PSMA-11 PET/CT. The existence of a PCa lesion was established according to a composite standard of truth based on all clinical data available collected during the follow-up period. Results: We included 294 patients. The detection rate was 69%. Per-patient sensitivity and specificity were both 70%. Patient disease management was changed in 68% of patients, and [⁶⁸Ga]Ga-PSMA-11 PET/CT impacted this change in 86% of patients. The treatment carried out on patient was considered effective in 89% of patients when guided by [⁶⁸Ga]Ga-PSMA-11 PET/CT versus 61% of patients when not guided by [⁶⁸Ga]Ga-PSMA-11 PET/CT (p < 0.001). Conclusions: [⁶⁸Ga]Ga-PSMA-11 PET/CT demonstrated high performance in locating PCa recurrence sites and impacted therapeutic management in nearly two out of three patients.

Simple new method for labelling of PSMA-11 with 68Ga in NaHCO3

BACKGROUND

Prostate specific membrane antigen (PSMA) is a type II membrane protein widely expressed on the surface of prostate cancer cells. One of its functions is to act as a receptor mediating the ligand internalization. This PSMA property is employed in the diagnostics and therapy of prostate cancer. Over the years, small molecules with high affinity for PSMA have been developed and labelled with positron emitters (e.g. ⁶⁸Ga, ¹⁸F, ¹¹C, ⁶⁴Cu, or ⁸⁶Y). One of these radiolabelled ligands, [⁶⁸Ga] PSMA-11, is one of the most widespread tracers for PET imaging of the prostate cancer. Many techniques have been proposed and tested for the ⁶⁸Ga labelling of PSMA-11. The aim of our work was to design a labelling method of PSMA-11 that minimizes number of the used chemicals and steps, providing quantitative labelling yield at laboratory temperature and may be easily automated.

METHODOLOGY

A⁶⁸Ge/⁶⁸Ga generator eluate in 0.1 M HCl was loaded on an activated Oasis MCX cartridge, and the cartridge was then thoroughly washed with water. The radionuclide ⁶⁸Ga was eluted from the cartridge with 0.1 M NaHCO₃ (pH = 8.5, n = 36) or with the same solution with pH adjusted to 7.2-9.0 (n = 38). Precursor PSMA-11 was mixed directly with the cartridge eluate of ⁶⁸Ga in 0.1 M NaHCO₃ of given pH. For the stability test, samples of ⁶⁸GaPSMA-11 in 0.1 M NaHCO₃ (pH 8.5) were mixed in ratio 1 : 1 with the following solutions: 0.1 M NaHCO₃ (pH 8.5), human serum, PBS and 0.9% NaCl. In order to estimate an effect of the time elapsed between ⁶⁸Ga elution from the cartridge in 0.1 M NaHCO₃ (pH 8.5) and the labelling onset of PSMA-11, the latter was initiated 0, 5, 10 and 20 min post elution and radiochemical yield was monitored. All the PSMA-11 labelled samples were subjected to radiochemical purity test using HPLC. The whole process starting from generator elution up to HPLC analysis commencement took 10-15 min.

RESULTS

Recovery of ⁶⁸Ga from cartridge Oasis MCX using 0.1 M NaHCO₃ at pH 8.5 was 71.5 ± 1.4%. Thirty six PSMA-11 samples (10 μg in reaction mixture) were labelled at pH 8.5 with total average radiochemical yield of 98 ± 2%. Recovery of ⁶⁸Ga from cartridge Oasis MCX using 0.1 M NaHCO₃ at variable pH of 7.2-9.0 was 62.5 ± 1.8% showing certain decrease with decreasing pH. A total of 138 samples of PSMA-11 were labelled with ⁶⁸ Ga at variable pH (7.2-9.0) and four different amounts of PSMA-11 (1, 2.5, 5 and 10 μg) resulting in the labelling yields of 54.0 ± 5.3%, 88.2 ± 3.2%, 99.4 ± 0.3% and 99.9 ± 0.1%, respectively. Irrespective of the pH, the radiolabelling yield was quantitative for the molar ratio PSMA-11: ⁶⁸Ga > 5000 : 1 in the reaction mixture. Stability tests in 0.1 M NaHCO₃ (pH 8.5), human serum, PBS and 0.9% NaCl revealed no observable release of ⁶⁸Ga from the ⁶⁸Ga-PSMA-11 complex within 3 h. Similarly, the delay between the ⁶⁸Ga elution from the Oasis MCX cartridge in 0.1 M NaHCO₃ (pH 8.5) and start of the labelling of PSMA-11 labelling has no effect on the radiochemical yield.

CONCLUSION

A new method of labelling PSMA-11 ligand with ⁶⁸Ga in 0.1 M NaHCO₃ using Oasis MCX cartridges was proposed, developed and tested. The results demonstrated that it is rapid, simple, reproducible and easy to automate.

Survey by the French Medicine Agency (ANSM) of the imaging protocol, detection rate, and safety of 68Ga-PSMA-11 PET/CT in the biochemical recurrence of prostate cancer in case of negative or equivocal 18F-fluorocholine PET/CT: 1084 examinations

Introduction

Despite growing evidence of a superior diagnostic performance of ⁶⁸Ga-PSMA-11 over ¹⁸F-fluorocholine (FCH) PET/CT, the number of PET/CT centres able to label on site with gallium-68 is still currently limited. Therefore, patients with biochemical recurrence (BCR) of prostate cancer frequently undergo FCH as the 1st-line PET/CT. Actually, the positivity rate (PR) of a second-line PSMA-11 PET/CT in case of negative FCH PET/CT has only been reported in few short series, in a total of 185 patients. Our aims were to check (1) whether the excellent PR reported with PSMA-11 is also obtained in BCR patients whose recent FCH PET/CT was negative or equivocal; (2) in which biochemical and clinical context a high PSMA-11 PET/CT PR may be expected in those patients, in particular revealing an oligometastatic pattern; (3) whether among the various imaging protocols for PSMA-11 PET/CT used in France, one yields a significantly highest PR; (4) the tolerance of PSMA-11.

Patients and methods

Six centres performed ⁶⁸Ga-PSMA-11 PET/CTs during the first 3 years of its use in France. Prior to each PET/CT, the patient’s data were submitted prospectively for authorisation to ANSM, the French Medicine Agency. The on-site readings of 1084 PSMA-11 PET/CTs in BCR patients whose recent FCH PET/CTs resulted negative or equivocal were pooled and analysed.

Results

(1) The overall PR was 68%; for a median serum PSA level (sPSA) of 1.7 ng/mL, an oligometastatic pattern (1–3 foci) was observed in 31% of the cases overall; (2) PR was significantly related to sPSA (from 41% if < 0.2 ng/mL to 81% if ≥ 2 ng/mL), to patients’ age, to initial therapy (64% if prostatectomy vs. 85% without prostatectomy due to frequent foci in the prostate fossa), to whether FCH PET/CT was negative or equivocal (PR = 62% vs. 82%), and to previous BCR (PR = 63% for 1st BCR vs. 72% in case of previous BCR); (3) no significant difference in PR was found according to the imaging protocol: injected activity, administration of a contrast agent and/or of furosemide, dose length product, one single or multiple time points of image acquisition; (4) no adverse event was reported after PSMA-11 injection, even associated with a contrast agent and/or furosemide.

Conclusion

Compared with the performance of PSMA-11 PET/CT in BCR reported independently of FCH PET/CT in 6 large published series (n > 200), the selection based on FCH PET/CT resulted in no difference of PSMA-11 PR for sPSA < 1 ng/mL but in a slightly lower PR for sPSA ≥ 1 ng/mL, probably because FCH performs rather well at this sPSA and very occult BCR was over-represented in our cohort. An oligometastatic pattern paving the way to targeted therapy was observed in one fourth to one third of the cases, according to the clinico-biochemical context of the BCR. Systematic dual or triple acquisition time points or administration of a contrast agent and/or furosemide did not bring a significant added value for PSMA-11 PET/CT positivity and should be decided on individual bases.

Current status of PSMA PET imaging in prostate cancer

The past decade has witnessed the rising popularity and acceptance of molecular definitions on disease management. Prostate-specific membrane antigen (PSMA), in light of its molecular nature and cytokinetic properties, has rapidly become the target for development of a variety of functional tracers for PET/CT evaluation of prostate cancer. The most commonly used PSMA-binding analog is ⁶⁸ Ga-labeled PSMA-11, which is now widely applied in both research and clinical settings. Literature data in the recent years have been enriched by a number of meta-analyses and systemic reviews on the evolving role of PSMA PET in primary diagnosis, staging, detection of biochemical recurrence after primary cancer treatment, identification, and significance of oligometastasis, as well as in restaging and treatment monitoring. Being a highly sensitive and reasonably specific molecular tracer, PSMA-binding analogs have a high potential to possess the majority of imaging characteristics required for a variety of management decisions in prostate malignancy.

Evaluation of the clinical use of PET/CT with 68Ga-PSMA for the assessment of biochemical recurrence of low or intermediate-risk prostate cancer

RATIONALE

⁶⁸Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (PET-PSMA) has shown promising performance for the assessment of biochemical recurrence of prostate cancer in high-risk patients, defined by D´Amico et al. criteria. Little evidence for the impact of this diagnostic method for patients at low or intermediate risk, in terms of management and benefits of subsequent treatment, is available.

METHODS

Data from 57 patients with low and intermediate-risk prostate cancer and biochemical recurrence underwent PET-PSMA were examined retrospectively. Images were analyzed and findings were compared with clinical data. Indications for the PET-PSMA imaging, study positivity/negativity, lesion locations, Gleason (ISUP) score, prostate-specific antigen (PSA) level on the examination date, postexamination treatment, and management were evaluated.

RESULTS

PET-PSMA findings were negative for 28 (49.12%) patients, 11 of whom received salvage radiotherapy (S-RT; with or without HT; PSA levels declined significantly in 10 (90.9%) of these patients compared with levels in those not undergoing S-RT. Positive PET-PSMA findings enabled the accurate identification of patients who benefited from salvage pelvic RT for local disease control and those who responded satisfactorily to systemic treatment.

CONCLUSION

PET-PSMA is useful for the assessment of biochemical recurrence in prostate cancer patients with prostate cancer at low and intermediate-risk.

68 Ga-PSMA-PET/CT helps to select patients for salvage radical prostatectomy with local recurrence after primary radiotherapy for prostate cancer

OBJECTIVE

To investigate the diagnostic performance of gallium-68 prostate-specific membrane antigen positron emission tomography/computed tomography (⁶⁸ Ga-PSMA PET/CT) in patients with recurrent prostate cancer with regard to the presence of lymph node metastases (LNM) and local recurrences after primary radiotherapy.

PATIENTS AND METHODS

We retrospectively reviewed 142 patients following salvage radical prostatectomy (sRP), 50 of which had a ⁶⁸ Ga-PSMA PET/CT performed as a preoperative staging module. Predictive clinical parameters were analysed in a multivariate Cox regression analysis. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) and the accuracy of ⁶⁸ Ga-PSMA PET/CT were analysed with regard to LNM and local recurrence.

RESULTS

In all, 613 lymph nodes were resected in 40 patients and 23 lymph nodes had metastatic deposits in 14 patients. In all patients local recurrence could have been found with ⁶⁸ Ga-PSMA PET/CT. Sensitivity, specificity, PPV and NPV and accuracy on a per lymph node basis were 34.78% (16.38-57.2%), 100% (99.38-100%), 100%, 97.52% (96.69-98.15%) and 97.55% (96.00-98.62%). For detecting local recurrence, the sensitivity and PPV were both 100% with an accuracy of 100% (92.89-100%).

CONCLUSION

⁶⁸ Ga-PSMA PET/CT should be the standard imaging in biochemical recurrent prostate cancer. With this imaging module one detects first local recurrence and can detect locoregional and distant metastases more precisely than standard CT and bone scan.

Novel PET imaging methods for prostate cancer

INTRODUCTION

Prostate cancer is a common neoplasm but conventional imaging methods such as CT and bone scan are often insensitive. A new class of PET agents have emerged to diagnose and manage prostate cancer.

METHODS

The relevant literature on PET imaging agents for prostate cancer was reviewed.

RESULTS

This review shows a broad range of PET imaging agents, the most successful of which is prostate specific membrane antigen (PSMA) PET. Other agents either lack the sensitivity or specificity of PSMA PET.

CONCLUSION

Among the available PET agents for prostate cancer, PSMA PET has emerged as the leader. It is likely to have great impact on the diagnosis, staging and management of prostate cancer patients.

Diagnostic Performance of 68Ga-PSMA-11 Positron-emission-tomography/Computed-tomography in a Large Cohort of Patients with Biochemical Recurrence of Prostate Carcinoma

Gallium-68 (Ga) prostate-specific-membrane-antigen positron-emission-tomography/computed-tomography is a highly promising method for imaging primary and recurrent prostate cancer. These dual-modality imaging technologies enable whole-body functional and anatomical evaluation in a single session. This study investigated the performance of Ga-prostate-specific-membrane-antigen-11 positron-emission-tomography/computed-tomography for detecting prostate carcinoma in patients with rising prostate-specific-antigen after primary therapy. Six hundred sixty (660) patients with biochemical recurrence referred for positron-emission-tomography/computed-tomography with Ga-prostate-specific-membrane-antigen-11 were evaluated retrospectively. Prostate-specific-antigen-stratified cohorts of pathological scan results were analyzed, and relationships between prostate-specific-antigen kinetics and PSMA-positive tumor lesions were correlated. Gallium-68 prostate-specific-membrane-antigen-11 positron-emission-tomography/computed-tomography showed a pathological prostate-specific-membrane-antigen uptake in 76% (500 of 660 patients). Positive scans were positively associated with prostate-specific-antigen (p<0.001). For patients with prostate-specific-antigen <0.2 ng mL, the PSMA-positive tumor lesions rate was 41%. Patients with prostate-specific-antigen of 0.2-<0.5 ng mL, 0.5-<1.0 ng mL, 1.0-<2.0 ng mL, and 2.0-<5.0 ng mL showed rates of 44.7%, 61.7%, 72.3%, 85.2%, respectively, and for prostate-specific-antigen of ≥5.0 ng mL it increased to 94%. Prostate-specific-antigen velocity was also correlated with PSMA-positive tumor lesions (p<0.001). In contrast, no association was found for prostate-specific-antigen doubling time (p=0.74). PSMA-positive tumor lesions were significantly increased in patients with primary intermediate- (Gleason Score7) and high-risk (Gleason Score>7) vs. low-risk prostate cancer (Gleason Score<7) (p<0.001). Our data confirm the high performance of Ga-prostate-specific-membrane-antigen positron-emission-tomography/computed-tomography for the detection of recurrent prostate cancer. This may alter treatment planning and has been documented in other studies as well.

Localization and restaging of carcinoma prostate by 68Gallium prostate-specific membrane antigen positron emission tomography computed tomography in patients with biochemical recurrence

INTRODUCTION

Radical prostatectomy (RP) and radical radiotherapy (RT) are well established primary curative options for localized prostate cancer. Despite technical improvements, prostate-specific antigen (PSA)-recurrence after RP and RT is a common clinical scenario. We aimed to assess the role of ⁶⁸Gallium (⁶⁸Ga) prostate-specific membrane antigen positron emission tomography computed tomography (PSMA PET/CT) in patients with biochemical recurrence of prostate cancer after RP or RT for the detection and localization recurrent and metastatic disease.

MATERIALS AND METHODS

We ambispectively (70 retrospective and 100 prospective) analyzed the data of men with biochemical recurrence post-RP and post-RT who were evaluated by ⁶⁸Ga PSMA PET/CT at our institute. We aimed to assess the relationship between serum PSA levels and the probability of having a positive scan in patients with recurrent prostate cancer.

RESULTS

The study included 170 men, all had adenocarcinoma of the prostate, 124/170 had previous RP and 46/170 had prior RT. The median serum PSA in the RP group was 1.8 ng/ml and 5.2 ng/ml in the RT group. In the post-RP cohort, the detection rate of ⁶⁸Ga PSMA PET/CT was 39.3% for PSA 0.2 to <0.5 ng/ml, 47.3% for PSA 0.5 to <1 ng/ml, 68.4% for PSA 1 to <2 ng/ml and 93.1% for PSA ≥2 ng/ml. In the post-RT group, the detection rate was 88.8% for PSA 2 to <4 ng/ml and 100% for PSA ≥4 ng/ml.

CONCLUSIONS

⁶⁸Ga PSMA PET/CT provides a novel imaging modality for the detection of prostate cancer recurrence and metastases at low posttreatment PSA levels, which may help in directing appropriate salvage treatments.

The Value of 68Ga-PSMA PET/CT Following Equivocal 18F-NaF PET/CT in Prostate Cancer Patients

Background: Inconclusive bone scans are a challenge but there is no consensus about follow-up imaging. We evaluated the use of ⁶⁸gallium-labelled prostate-specific membrane antigen (⁶⁸Ga-PSMA) PET/CT if ¹⁸F-sodium fluoride (¹⁸F-NaF) PET/CT was inconclusive. Methods: This retrospective study included patients with no previously known bone metastases who had one or more equivocal bone lesions on ¹⁸F-NaF PET/CT and underwent additional ⁶⁸Ga-PSMA PET/CT. The bone lesions were deemed as true metastases or not based on follow-up by surveying supplemental imaging modalities and hospital records. A subgroup of patients with “most valid follow-up” was created, which included patients with unmeasurable PSA after prostatectomy or subsequent imaging (additional ¹⁸F-NaF PET/CT, ⁶⁸Ga-PSMA PET/CT, CT, or MRI). Results: Of the 2918 patients referred for ¹⁸F-NaF PET/CT from the department of urology in the inclusion period, 51 (1.7%) were inconclusive regarding bone metastases and underwent additional ⁶⁸Ga-PSMA PET/CT. Thirteen of these patients (25%) were ultimately diagnosed with bone metastases. Patient-based sensitivity, specificity, and accuracy of additional ⁶⁸Ga-PSMA PET/CT were 100%, 95%, and 96%, respectively. In patients with “most valid follow-up”, the same parameters were 100%, 93%, and 94%, respectively. Conclusion: ⁶⁸Ga-PSMA PET/CT is an excellent complementary modality in when ¹⁸F-NaF PET/CT is equivocal.

PSMA-PET/CT-based Lymph Node Atlas for Prostate Cancer Patients Recurring After Primary Treatment: Clinical Implications for Salvage Radiation Therapy

BACKGROUND

Many patients experience recurrence of prostate cancer after radical prostatectomy.

OBJECTIVE

The aim of this study was to visually analyze typical patterns of lymph node (LN) involvement for prostate cancer (PC) patients with biochemical recurrence after radical prostatectomy and lymphadenectomy by creating a color-coded heat map using gallium-68 prostate-specific membrane antigen positron emission tomography (⁶⁸Ga-PSMA-PET) imaging. Further, we evaluated which LNs were covered by the Radiation Therapy Oncology Group (RTOG) clinical target volume (CTV) contouring guidelines.

DESIGN, SETTING, AND PARTICIPANTS

A total of 1653 ⁶⁸Ga-PSMA-PET/computed tomography (CT) datasets were screened retrospectively. After meeting the eligibility criteria, 233 patients with 799 LN metastases were included in our study.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We created a comprehensive three-dimensional color-coded LN atlas. Further, the coverage of LN metastases by RTOG CTV was assessed and stratification for risk factors was performed.

RESULTS AND LIMITATIONS

In the overall, mainly high risk, collective, complete coverage by the standard RTOG CTV was accomplished in 31.0% of all LN metastases. The vast majority of uncovered LNs are situated in the para-aortal, pararectal, paravesical, preacetabular, presacral, and inguinal regions. Concerning examined stratification factors, prostate-specific antigen (PSA) levels at the time of PET/CT imaging had the highest predictive value for extrapelvic metastatic LN spread. Every increase of 1 ng/mL in PSA raises the risk of metastases outside the CTV by a factor of 1.43.

CONCLUSIONS

We developed the first LN atlas for patients with recurrent PC using a heat map technique, in order to illustrate hot spots of LN recurrence. The vast majority of detected LNs are not covered by a standard CTV as recommended by the RTOG. Application of the standard RTOG CTV for pelvic irradiation in the salvage setting for high-risk PC patients seems to be inappropriate.

PATIENT SUMMARY

We visualized typical lymph node recurrence sites for patients after prostate cancer surgery.

PSMA-targeted Radiotracers versus 18F Fluciclovine for the Detection of Prostate Cancer Biochemical Recurrence after Definitive Therapy: A Systematic Review and Meta-Analysis

Background National guidelines endorse fluorine 18 (¹⁸F) fluciclovine PET/CT for the detection of prostate cancer (PCa) in men with biochemically recurrent PCa. The comparative performance between fluciclovine and gallium 68 or ¹⁸F prostate-specific membrane antigen (PSMA) PET/CT, a newer examination, is unclear. Purpose To compare the detection of biochemical recurrence using fluciclovine versus PSMA-targeted radiotracers in patients with a prostate-specific antigen (PSA) level less than 2 ng/mL. Materials and Methods With use of the Preferred Reporting Items for a Systematic Review and Meta-Analysis of Diagnostic Test Accuracy, or PRISMA-DTA, guidelines, a systematic review of PubMed and EMBASE databases between 2012 and 2019 was performed. Studies of fluciclovine PET/CT or PSMA PET/CT in biochemical recurrence were identified. PSA levels, clinical data, and reference standards were obtained when available. A random-effects model was applied to pooled estimates and 95% confidence intervals (CIs) around the prevalence of a positive examination, stratified according to PSA tier. Results Quantitative analysis included 482 patients (median age, 67 years; interquartile range, 67-67 years) in six fluciclovine studies and 3217 patients (median age, 68 years; interquartile range, 67-70 years) in 38 PSMA studies. Pooled detection rates for PSMA and fluciclovine were 45% (95% CI: 38%, 52%) and 37% (95% CI: 25%, 49%), respectively, for a PSA level less than 0.5 ng/mL (P = .46); 59% (95% CI: 52%, 66%) and 48% (95% CI: 34%, 61%) for a PSA level of 0.5-0.9 ng/mL (P = .19); and 80% (95% CI: 75%, 85%) and 62% (95% CI: 54%, 70%) for a PSA level of 1.0-1.9 ng/mL (P = .01). A reference standard was positive in 703 of 735 patients (96%) in the PSMA cohort and 247of 256 (97%) in the fluciclovine cohort. Conclusion Patient-level detection rates for biochemically recurrent prostate cancer were greater for prostate-specific membrane antigen-targeted radiotracers than fluciclovine for prostate specific antigen levels of 1.0-1.9 ng/mL. © RSNA, 2020 Online supplemental material is available for this article.

PSA and PSA Kinetics Thresholds for the Presence of 68Ga-PSMA-11 PET/CT-Detectable Lesions in Patients With Biochemical Recurrent Prostate Cancer

⁶⁸Ga-PSMA-11 positron-emission tomography/computed tomography (PET/CT) is commonly used for restaging recurrent prostate cancer (PC) in European clinical practice. The goal of this study is to determine the optimum time for performing these PET/CT scans in a large cohort of patients by identifying the prostate-specific-antigen (PSA) and PSA kinetics thresholds for detecting and localizing recurrent PC. This retrospective analysis includes 581 patients with biochemical recurrence (BC) by definition. The performance of ⁶⁸Ga-PSMA-11 PET/CT in relation to the PSA value at the scan time as well as PSA kinetics was assessed by the receiver-operating-characteristic-curve (ROC) generated by plotting sensitivity versus 1-specificity. Malignant prostatic lesions were identified in 77%. For patients that were treated with radical prostatectomy (RP) a PSA value of 1.24 ng/mL was found to be the optimal cutoff level for predicting positive and negative scans, while for patients previously treated with radiotherapy (RT) it was 5.75 ng/mL. In RP-patients with PSA value <1.24 ng/mL, 52% scans were positive, whereas patients with PSA ≥1.24 ng/mL had positive scan results in 87%. RT-patients with PSA <5.75 ng/mL had positive scans in 86% and for those with PSA ≥5.75 ng/mL 94% had positive scans. This study identifies the PSA and PSA kinetics threshold levels for the presence of ⁶⁸Ga-PSMA-11 PET/CT-detectable PC-lesions in BC patients.

Treatment of non-metastatic castration resistant prostate cancer in 2020: What is the best?

Lately the development of 3 novel second-generation androgen receptor antagonists (enzalutamide, apalutamide, and darolutamide) chanced the treatment landscape of nonmetastatic castration-resistant prostate cancer. After proofing their clinical efficacy in large phase III registration trials with good compatibilities and tolerable side effects currently all 3 substances are Food and Drug Administration-approved in nonmetastatic castration-resistant prostate cancer. The present short review article provides an overview about these new treatment options and discusses their use in daily routine focusing on patient selection as well as on the impact of novel sensitive imaging modalities like prostate-specific membrane antigen-positron-emission tomography for detection of this stage of disease.

Molecular Imaging in Photon Radiotherapy

Nowadays, more than ever before, the treatment of cancer patients requires an interdisciplinary approach more than ever. Radiation therapy (RT) has become an indispensable pillar of cancer treatment early on, offering a local, curative treatment option and symptom control in palliative cases.

The positivity rate of 68Gallium-PSMA-11 ligand PET/CT depends on the serum PSA-value in patients with biochemical recurrence of prostate cancer

Background: The aim of the present study is to analyze the efficacy of 68Gallium (Ga)-PSMA-11 PET/CT for detecting and localizing recurrent prostate carcinoma (PC) in patients with different prostate-specific antigen (PSA), PSA velocity (PSAvel) and doubling time (PSAdt).

Results: The PR of 68Ga-PSMA-11 PET/CT showed a positive relationship with PSA levels. Even at restaging PSA-values (PSAV) of lower than 0.2 ng/ml, PR was 41%. For PSAV of 0.2-<0.5 ng/ml the PR was 45%, 62% for PSAV of 0.5-<1.0 and 72% for PSAV of 1.0-<2.0 ng/ml. The PR increased to 85% for PSAV of 2.0-<5.0 and reached 94% at PSAV of ≥5.0 ng/ml. At PSA of <1 ng/ml/y the PR of PSAvel was 50% and increased to 98% at PSA >5 ng/ml/y. No significant association was found for PSAdt.

Methods: PET/CT scans of 660 patients with biochemical recurrence (BCR) after primary therapy of PC were included in the analysis. We correlated serum PSA levels, measured at the time of imaging with PSMA PET/CT-positivity rates (PR) as well as PSAvel (in 225 patients) and PSAdt (660 patients). Additionally we compared the incidence of localized disease to metastases as related to these PSA-biomarkers.

Conclusion: We have shown, in a large cohort of patients, that 68Ga-PSMA-11 PET/CT is a sensitive tool for restaging PC and has a high detection efficacy, even in patients with very low PSA levels (<0.2 ng/ml). Thus 68Ga-PSMA-11 PET/CT both identify and localize recurrent disease with implications for a more direct treatment approach (localized vs. systemic therapy).

Detection Rate and Localization of Prostate Cancer Recurrence Using 68Ga-PSMA-11 PET/MRI in Patients with Low PSA Values ≤ 0.5 ng/mL

A first analysis of simultaneous ⁶⁸Ga-prostate-specific membrane antigen (PSMA)-11 PET/MRI showed some improvement in the detection of recurrent disease at low serum prostate specific antigen (PSA) values below 0.5 ng/mL compared with the already high detection rate of ⁶⁸Ga-PSMA-11 PET/CT. We therefore focused on all patients with biochemical recurrence and PSA values no higher than 0.5 ng/mL to assess the detection rate for ⁶⁸Ga-PSMA-11 PET/MRI. Methods: We retrospectively analyzed a cohort of 66 consecutive patients who underwent ⁶⁸Ga-PSMA-11 PET/MRI for biochemical recurrence with a PSA value no higher than 0.5 ng/mL at our institution. Median PSA level was 0.23 ng/mL (range, 0.03-0.5 ng/mL). Detection of PSMA-positive lesions within the prostate fossa, local and distant lymph nodes, bones, or visceral organs was recorded. In addition, all scans with ⁶⁸Ga-PSMA-11 PET/MRI-positive lesions were retrospectively assessed to analyze if lesions were detected inside or outside a standard salvage radiotherapy volume. Results: Overall, in 36 of 66 patients (54.5%) PSMA-positive lesions were detected; in 26 of 40 (65%) patients with a PSA level between 0.2 and 0.5 ng/mL and in 10 of 26 (38.5%) patients with a PSA level less than 0.2 ng/mL. Even at those low PSA values, only 8 of 66 (12.1%) patients had exclusive local recurrence. Lymph nodes were detected in 23 patients and bone metastases in 5 on ⁶⁸Ga-PSMA-11 PET/MRI. In 26 of 66 patients (39.4%), PSMA-positive lesions were located outside a standard salvage radiotherapy volume. Conclusion: Our data confirm that ⁶⁸Ga-PSMA-11 PET/MRI has a high detection rate for recurrent prostate cancer, even at low PSA levels no higher than 0.5 ng/mL. In addition, we show that ⁶⁸Ga-PSMA-11 PET/MRI detected PSMA-positive lesions outside a standard salvage radiotherapy volume in 39.4% of all patients.

[Advanced Prostate Cancer Consensus Conference 2017 : Discussion of the recommendations for diagnosis and treatment of metastatic prostate cancer by a German panel of experts]

In March 2017 the 'Advanced Prostate Cancer Consensus Conference' (APCCC) took place in St. Gallen (Switzerland). The APCCC-panelists are internationally well known experts. With the actual data in mind they discussed treatment options for patients with advanced prostate cancer in order to update the international APCCC-recommendations from the previous meeting in 2015. Recently these consensus recommendations have been published in "European Urology".A group of German experts discussed this year APCCC-votes during the meeting and the recommendations that were concluded from the votes from the German perspective. Reasons for an additional German discussion are country-specific variations that may have influenced the APCCC-votes und recommendations. Due to the concept of the APCCC-meeting the wording of the questions could not always be as necessary.One focus of this year consensus discussion was the treatment of metastatic castration-naive prostate cancer (mCNPC). There are new data which may also influence the therapeutic situation of patients with metastatic castration-resistant prostate cancer (mCRPC). Further points of discussion were the impact of new imaging procedures in the clinical setting as well as the treatment of oligometastatic prostate cancer.

Location of Recurrence by Gallium-68 PSMA-11 PET Scan in Prostate Cancer Patients Eligible for Salvage Radiotherapy

OBJECTIVE

To identify locations of recurrence after radical prostatectomy (RP) with prostate-specific antigen (PSA) <2 by Gallium-68 prostate-specific membrane antigen (PSMA)-11 Positron Emission Tomography (PET) imaging, and to determine whether standard nodal radiation fields would cover the location of prostate cancer recurrence.

MATERIALS AND METHODS

We performed a retrospective review of patients with PSMA-PET imaging for biochemical recurrence following RP with PSA ≤2.0 ng/mL and assessed if the recurrent disease was within standard radiation target volumes. We compared patient and clinical variables between men with recurrences covered by standard salvage radiation fields and those with recurrences outside of standard fields.

RESULTS

We identified 125 patients for study inclusion. The median PSA at imaging was 0.40 ng/mL (interquartile range 0.28-0.63). PSMA-avid disease was found in 66 patients (53%). Of these, 25 patients (38%) had PSMA-avid lesions found outside of the pelvis, 33 (50%) had lesions confined to the pelvic lymph nodes and prostate bed, and 8 (12%) men had PSMA-avid recurrence only in the prostate bed. Salvage radiation including standard Intensity Modulated Radiation Therapy (IMRT) pelvic nodal volumes would not cover PSMA-avid nodal disease in 38 men (30%). PSA at the time of imaging was statistically associated with having PSMA-avid disease outside of standard nodal fields (P <.01).

CONCLUSION

The 68Ga-PSMA-11 PET detects disease in a majority of patients with PSA ≤2.0 following RP. Nearly one-third of men had PSMA-avid disease that would be missed by standard radiation fields. This imaging modality may dramatically impact the design and use of post-RP salvage radiotherapy.