A Prospective Comparison of 18F-prostate-specific Membrane Antigen-1007 Positron Emission Tomography Computed Tomography, Whole-body 1.5 T Magnetic Resonance Imaging with Diffusion-weighted Imaging, and Single-photon Emission Computed Tomography/Computed Tomography with Traditional Imaging in Primary Distant Metastasis Staging of Prostate Cancer (PROSTAGE)

Improving sensitivity through data augmentation with synthetic lymph node metastases for AI-based analysis of PSMA PET-CT images

BACKGROUND

We developed a fully automated artificial intelligence (AI)AI-based-based method for detecting suspected lymph node metastases in prostate-specific membrane antigen (PSMA)(PSMA) positron emission tomography-computed tomography (PET-CT)(PET-CT) images of prostate cancer patients by using data augmentation that adds synthetic lymph node metastases to the images to expand the training set.

METHODS

Synthetic data were derived from original training images to which new synthetic lymph node metastases were added. Thus, the original training set from a previous study (n = 420) was expanded by one synthetic image for every original image (n = 840), which was used to train an AI model. The performance of the AI model was compared to that of nuclear medicine physicians and a previously developed AI model. The human readers were alternately used as a reference and compared to either another reading or AI model.

RESULTS

The new AI model had an average sensitivity of 84% for detecting lymph node metastases compared with 78% for human readings. Our previously developed AI method without synthetic data had an average sensitivity of 79%. The number of false positive lesions were slightly higher for the new AI model (average 3.3 instances per patient) compared to human readings and the previous AI model (average 2.8 instances per patient), while the number of false negative lesions was lower.

CONCLUSIONS

Creating synthetic lymph node metastases, as a form of data augmentation, on [18F]PSMA-1007F]PSMA-1007 PETPET-CT-CT images improved the sensitivity of an AI model for detecting suspected lymph node metastases. However, the number of false positive lesions increased somewhat.

Diagnostic Accuracy of 18F-Prostate Specific Membrane Antigen (PSMA) PET/CT Radiotracers in Staging and Restaging of Patients With High-Risk Prostate Cancer or Biochemical Recurrence: An Overview of Reviews

The aim of this overview was to consolidate existing evidence syntheses and provide a comprehensive overview of the evidence for 18F-prostate specific membrane antigen (PSMA) PET/CT in the staging of high-risk prostate cancer and restaging after biochemical recurrence. An overview of reviews was performed and reported in line with the preferred reporting items for overview of reviews (PRIOR) statement and synthesis without meta-analysis (SWiM) reporting guidelines. A comprehensive database and grey literature search were conducted up to July 18, 2023. Systematic reviews were assessed using the risk of bias in systematic reviews (ROBIS) tool. The certainty of the evidence was assessed using grading of recommendations, assessment, development and evaluations (GRADE). 11 systematic reviews were identified; 10 were at high or unclear risk of bias. Evidence reported on a per-patient, per-lymph node, and per-lesion basis for sensitivity, specificity and overall accuracy was identified. There was a lack of data on dose, adverse events and evidence directly comparing 18F-PSMA PET/CT to other imaging modalities. Evidence with moderate to very low certainty indicated high sensitivity, specificity and accuracy of 18F-PSMA PET/CT in patients with high-risk prostate cancer and biochemical recurrence. There was considerably lower certainty evidence and greater variability in effect estimates for outcomes for the combined intermediate/high-risk cohort. While evidence gaps remain for some outcomes, and most systematic reviews were at high or unclear risk of bias, the current evidence base is broadly supportive of 18F-PSMA PET/CT imaging in the staging and restaging of patients with high-risk prostate cancer and biochemical recurrence.

Radiographic Progression at Castration-Resistant Prostate Cancer Diagnosis: A Prognostic Indicator of Metastatic Hormone-Sensitive Prostate Cancer

BACKGROUND

The critical role of radiographic assessment at the time of castration-resistant prostate cancer (CRPC) diagnosis is underscored by this study. We performed a retrospective analysis of radiographic changes in metastasis from the time of diagnosis of metastatic hormone-sensitive prostate cancer (mHSPC) to CRPC diagnosis. We also explored its impact on prognosis post-CRPC.

MATERIALS AND METHODS

We retrospectively analyzed 98 men who underwent radiographic examinations (bone scans and computed tomography [CT]) at the time of CRPC diagnosis. When radiographic studies demonstrated progression at CRPC diagnosis, patients were assigned to the radiographic progressive disease (rPD) group. The remaining patients were placed in the "non-rPD" group. The overall survival (OS) post-CRPC was compared between the 2 groups.

RESULTS

The median OS post-CRPC was significantly shorter in the rPD group (n = 50) compared to the non-rPD group (n = 48) (32 months vs. not reached, P = .0124). Multivariate analysis showed that radiographic progression and shorter time to CRPC were associated with a shorter OS post-CRPC (hazard ratio [HR] = 3.14; 95% confidence interval [CI], 1.21-8.12, P = .019).

CONCLUSION

Radiographic progression at the point of CRPC diagnosis independently predicts a shorter OS post-CRPC in patients with mHSPC. Therefore, assessing radiographic changes at the time of CRPC diagnosis could be instrumental in managing CRPC in patients with mHSPC.

A systematic review and meta-analysis to evaluate the diagnostic accuracy of PSMA PET/CT in the initial staging of prostate cancer

BACKGROUND

Positron Emission Tomography-Computed Tomography using Prostate-Specific Membrane Antigen (PSMA PET/CT) is notable for its superior sensitivity and specificity in detecting recurrent PCa and is under investigation for its potential in pre-treatment staging. Despite its established efficacy in nodal and metastasis staging in trial setting, its role in primary staging awaits fuller validation due to limited evidence on oncologic outcomes. This systematic review and meta-analysis aims to appraise the diagnostic accuracy of PSMA PET/CT compared to CI for comprehensive PCa staging.

METHODS

Medline, Scopus and Web of science databases were searched till March 2023. Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines were followed to identify eligible studies. Primary outcomes were specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) of PSMA PET/CT for local, nodal and metastatic staging in PCa patients. Due to the unavailability of data, a meta-analysis was feasible only for detection of seminal vesicles invasion (SVI) and LNI.

RESULTS

A total of 49 studies, comprising 3876 patients, were included. Of these, 6 investigated accuracy of PSMA PET/CT in detection of SVI. Pooled sensitivity, specificity, PPV and NPV were 42.29% (95%CI: 29.85-55.78%), 87.59% (95%CI: 77.10%-93.67%), 93.39% (95%CI: 74.95%-98.52%) and 86.60% (95%CI: 58.83%-96.69%), respectively. Heterogeneity analysis revealed significant variability for PPV and NPV. 18 studies investigated PSMA PET/CT accuracy in detection of LNI. Aggregate sensitivity, specificity, PPV and NPV were 43.63% (95%CI: 34.19-53.56%), 85.55% (95%CI: 75.95%-91.74%), 67.47% (95%CI: 52.42%-79.6%) and 83.61% (95%CI: 79.19%-87.24%). No significant heterogeneity was found between studies.

CONCLUSIONS

The present systematic review and meta-analysis highlights PSMA PET-CT effectiveness in detecting SVI and its good accuracy in LNI compared to CI. Nonetheless, it also reveals a lack of high-quality research on its performance in clinical T staging, extraprostatic extension and distant metastasis evaluation, emphasizing the need for further rigorous studies.

The impact of locoregional treatments for metastatic castration resistant prostate cancer on disease progression: real life experience from a multicenter cohort

BACKGROUND

Available data on medical treatment of metastatic castration resistant prostate cancer (mCRPC) support the use of more than one therapy line to delay chemotherapy. We evaluate in a longitudinal real life multicenter cohort, the oncological outcome of mCRPC patients treated with Abiraterone Acetate (AA) and Enzalutamide (EZ) in a chemo-naïve setting, who received locoregional treatments for subsequent development of oligorecurrent disease.

METHODS

We prospectively collected data on chemo-naïve mCRPC patients, who received either AA or EZ as first or second line treatment between Oct-2012 and Nov-2020 at 5 centers. High-volume disease at mCRPC onset was defined as bulky positive nodes (≥5 cm) or more than 6 bone metastases. Survival probabilities were computed at 12, 24, 48 and 60 months after treatment start. The impact of loco-regional treatments on progression free survival (PFS) were assessed with the Kaplan-Meier method and the log-rank test was applied.

RESULTS

Overall, 117 chemo-naive mCRPC patients received a first line therapy. Fifty-seven (48.7%) patients received AA and 60 (51.3%) received EZ. Eight (6.7%) patients underwent salvage chemotherapy after first line failure. Overall, 28 patients shifted to a second line therapy. Two-yr progression-free, cancer-specific and overall survival probabilities were 65.5%, 82.2% and 78.4% respectively. Since diagnosis of mCRPC, oligo progression occurred in 25 patients who received stereotactic radiation therapy (23/25, 92%) focused on metastasis (4 nodal sites and 19 bones) or salvage lymph node dissection (2/25, 8%). At Kaplan-Meier analysis, patients with low volume disease displayed higher PFS probabilities (log rank p = 0.009) and in this subgroup of patients loco-regional treatments had a significant impact on PFS (p = 0.048), while it was negligible in the whole cohort and in patients with high volume disease (p = 0.6 and p = 0.75).

CONCLUSIONS

Low-volume mCRPC patients are exposed to improved PFS and seem to benefit from locoregional treatments.

Prostate-Specific Membrane Antigen PET/Computed Tomography: Pearls and Pitfalls

Prostate-specific membrane antigen PET (PSMA-PET) has emerged as a powerful imaging tool for prostate cancer primary staging, biochemical recurrence, and advanced disease assessment. This article offers a concise overview of the benefits and challenges associated with PSMA-PET for prostate cancer evaluation. The article highlights the advantages of PSMA-PET over conventional imaging, such as its higher sensitivity and specificity for detecting metastases, and the potential for guiding personalized treatment decisions. However, it also explores the limitations and potential pitfalls for interpretation. Overall, the article aims to provide valuable insights for clinicians and diagnostic imaging physicians in clinical practice.

The Probability of Metastases Within Different Prostate-specific Antigen Ranges Using Prostate-specific Membrane Antigen Positron Emission Tomography in Patients with Newly Diagnosed Prostate Cancer

Background and objectives

The association between prostate-specific antigen (PSA) level and probability of metastatic disease on prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) has not yet been established in patients with newly diagnosed prostate cancer (PCa). Our objective was to assess the probability of metastatic disease within different PSA ranges using PSMA PET/CT for initial staging of PCa, and to identify both the anatomical distribution and the predictors of metastases on PSMA PET/CT.

Methods

In total, 2193 patients with newly diagnosed PCa were retrospectively studied. PSMA PET/CT was performed for staging purposes between January 2017 and May 2022. The proportion of patients with PSMA-avid metastases, stratified by PSA level, was studied. A vast majority of patients in whom at least one high-risk prognostic factor was present underwent PSMA PET/CT. A multivariable logistic regression analysis was performed to identify the predictors of metastases on PSMA PET/CT using clinical, biochemical, radiological, and pathological variables.

Key findings and limitations

The median PSA level at PSMA PET/CT was 14.1 ng/ml. Any metastatic disease (miN1-M1a-c) was observed in 34.7% (763/2193) of all patients and distant metastases (miM1a-c) in 25.4% (557/2193) of patients. The presence of any metastatic disease increased with PSA levels, being 15.4% in men with PSA levels <10 ng/ml and 87.5% in men with PSA levels >100 ng/ml. The multivariable logistic regression analysis found significant associations between the presence of any metastatic disease and PSA subgroups, clinical tumor stage ≥T2, grade group >3, and radiological tumor stage ≥T3b.

Conclusions and clinical implications

This is the first large epidemiological study in patients with PCa demonstrating the association between PSA subgroups and metastatic disease on modern imaging PSMA PET/CT. Data from this study can be used to counsel patients on the probability of metastatic disease at the time of PSA screening and to provide guidance on existing guidelines.

Patient summary

The prostate-specific antigen level could be used to assess the risk of metastases on prostate-specific membrane antigen positron (PSMA) emission tomography/computed tomography (PET/CT). This knowledge is valuable for selecting patients who will benefit most from metastatic screening with PSMA PET/CT.

Bone Metastasis in Prostate Cancer: Bone Scan Versus PET Imaging

Prostate cancer is the second most common cause of malignancy among men, with bone metastasis being a significant source of morbidity and mortality in advanced cases. Detecting and treating bone metastasis at an early stage is crucial to improve the quality of life and survival of prostate cancer patients. This objective strongly relies on imaging studies. While CT and MRI have their specific utilities, they also possess certain drawbacks. Bone scintigraphy, although cost-effective and widely available, presents high false-positive rates. The emergence of PET/CT and PET/MRI, with their ability to overcome the limitations of standard imaging methods, offers promising alternatives for the detection of bone metastasis. Various radiotracers targeting cell division activity or cancer-specific membrane proteins, as well as bone seeking agents, have been developed and tested. The use of positron-emitting isotopes such as fluorine-18 and gallium-68 for labeling allows for a reduced radiation dose and unaffected biological properties. Furthermore, the integration of artificial intelligence (AI) and radiomics techniques in medical imaging has shown significant advancements in reducing interobserver variability, improving accuracy, and saving time. This article provides an overview of the advantages and limitations of bone scan using SPECT and SPECT/CT and PET imaging methods with different radiopharmaceuticals and highlights recent developments in hybrid scanners, AI, and radiomics for the identification of prostate cancer bone metastasis using molecular imaging.

Molecularly Engineered Room-Temperature Phosphorescence for Biomedical Application: From the Visible toward Second Near-Infrared Window

Phosphorescence, characterized by luminescent lifetimes significantly longer than that of biological autofluorescence under ambient environment, is of great value for biomedical applications. Academic evidence of fluorescence imaging indicates that virtually all imaging metrics (sensitivity, resolution, and penetration depths) are improved when progressing into longer wavelength regions, especially the recently reported second near-infrared (NIR-II, 1000-1700 nm) window. Although the emission wavelength of probes does matter, it is not clear whether the guideline of "the longer the wavelength, the better the imaging effect" is still suitable for developing phosphorescent probes. For tissue-specific bioimaging, long-lived probes, even if they emit visible phosphorescence, enable accurate visualization of large deep tissues. For studies dealing with bioimaging of tiny biological architectures or dynamic physiopathological activities, the prerequisite is rigorous planning of long-wavelength phosphorescence, being aware of the cooperative contribution of long wavelengths and long lifetimes for improving the spatiotemporal resolution, penetration depth, and sensitivity of bioimaging. In this Review, emerging molecular engineering methods of room-temperature phosphorescence are discussed through the lens of photophysical mechanisms. We highlight the roles of phosphorescence with emission from visible to NIR-II windows toward bioapplications. To appreciate such advances, challenges and prospects in rapidly growing studies of room-temperature phosphorescence are described.

Prostate-specific antigen doubling time predicts the efficacy of site-directed therapy for oligoprogressive castration-resistant prostate cancer

Background

In recent years, site-directed therapies (SDTs) targeting progressive lesions in patients with oligometastatic prostate cancer have attracted attention. However, whether they effectively treat oligoprogressive castration-resistant prostate cancer (CRPC) remains unclear. Here, we investigated the efficacy of SDT in patients with oligoprogressive CRPC and identified prognostic factors.

Methods

We reviewed 59 patients with oligoprogressive CRPC who underwent SDT targeting prostate or metastatic lesions between April 2014 and March 2022. We evaluated the associations between several pretreatment clinical variables and treatment procedures and a >50% prostate-specific antigen (PSA) response, progression-free survival (PFS), and time to next treatment (TTNT).

Results

A PSA response of >50% was observed in 66% of patients. The median PFS and TTNT were 8.3 months and 9.9 months, respectively. Patients with PSA doubling time ≥6 months showed a higher >50% PSA response rate (87% vs. 45%; P < 0.001), longer PFS (median, 15.0 vs. 5.0 months; P < 0.001), and longer TTNT (median, 16.3 vs. 5.9 months; P < 0.001) than patients with PSA doubling time <6 months. In multivariate analyses, a PSA doubling time of ≥6 months independently predicted a >50% PSA response, favorable PFS, and TTNT (P = 0.037, 0.025, and 0.017, respectively).

Conclusion

PSA doubling time of ≥6 months may be a key indicator of the favorable efficacy of SDT for oligoprogressive CRPC.

Identification of the Optimal Candidates for Nodal Staging with Extended Pelvic Lymph Node Dissection Among Prostate Cancer Patients Who Underwent Preoperative Prostate-specific Membrane Antigen Positron Emission Tomography. External Validation of the Memorial Sloan Kettering Cancer Center and Briganti Nomograms and Development of a Novel Tool

BACKGROUND

Although the therapeutic role of extended pelvic lymph node dissection (ePLND) in patients with prostate cancer (PCa) is still under debate, this procedure is recommended for staging purposes in selected cases. Nomograms for predicting lymph node invasion (LNI) do not account for prostate-specific membrane antigen (PSMA) positron emission tomography (PET) imaging, which is characterized by a high negative predictive value for nodal metastases.

OBJECTIVE

To externally validate models predicting LNI in patients with miN0M0 PCa at PSMA PET and to develop a novel tool in this setting.

DESIGN, SETTING, AND PARTICIPANTS

Overall, 458 patients with miN0M0 disease undergoing radical prostatectomy (RP) and ePLND at 12 centers between 2017 and 2022 were identified.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSES

Available tools were externally validated using calibration plots, the area under the receiver operating characteristic curve (AUC), and decision curve analyses to assess calibration, discrimination, and the net benefit. A novel coefficient-based model was developed, internally validated, and compared with available tools.

RESULTS AND LIMITATIONS

Overall, 53 patients (12%) had LNI. The AUC was 69% for the Briganti 2012, 64% for the Briganti 2017, 73% for the Briganti 2019, and 66% for the Memorial Sloan Kettering Cancer Center nomogram. Multiparametric magnetic resonance imaging stage, biopsy grade group 5, the diameter of the index lesion, and the percentage of positive cores at systematic biopsy were independent predictors of LNI (all p ≤ 0.04). Internal cross-validation confirmed a coefficient-based model with AUC of 78%, better calibration, and a higher net benefit in comparison to the other nomograms assessed. Use of a 5% cutoff would have spared 47% ePLND procedures (vs 13% for the Briganti 2019 nomogram) at the cost of missing only 2.1% LNI cases . The lack of central review of imaging and pathology represents the main limitation.

CONCLUSIONS

Tools for predicting LNI are associated with suboptimal performance for men with miN0M0 PCa. We propose a novel model for predicting LNI that outperforms available tools in this population.

PATIENT SUMMARY

Tools currently used to predict lymph node invasion (LNI) in prostate cancer are not optimal for men with negative node findings on PET (positron emission tomography) scans, leading to a high number of unnecessary extended pelvic lymph node dissection (ePLND) procedures. A novel tool should be used in clinical practice to identify candidates for ePLND to reduce the risk of unnecessary procedures without missing LNI cases.

Current role of PSMA-PET imaging in the clinical management of prostate cancer

Despite the developments of the last few years, metastatic castration-resistant prostate cancer (PC) remains a deadly disease. Until recently, almost all guidelines recommended magnetic resonance imaging (MRI) or computed tomography (CT) for the initial staging and local/systematic recurrence. Positron emission tomography/computed tomography (PET/CT) with prostate-specific membrane antigen (PSMA) at the present stage, emerged as a promising diagnostic imaging tool for PC. PSMA PET/CT alone or in combination with multiparametric magnetic resonance imaging (mpMRI) can improve the detection of clinically significant PC, especially for Prostate Imaging Reporting & Data System (PI-RADS) = 3 lesions. In addition, PSMA PET/CT is more accurate than CT and bone scan for intermediate to high-risk disease at the initial staging. Contrariwise, a negative PET is not useful for surgeons to avoid a pelvic nodal dissection. PET-PSMA imaging is appropriate for prostate-specific antigen (PSA) persistence or PSA rise from undetectable level after radical prostatectomy or for PSA rise above nadir after definitive radiotherapy. Also, it is recommended for patients fit for curative salvage treatment. It should be noted that in patients, candidates for radionuclide therapy with Lutetium-177 (117Lu), a PSMA strong expression from PET/CT at baseline is considered necessary. This review summarizes the evolution of PSMA PET/CT and its current role in the management of PC.

PSMA PET/CT in Castration-Resistant Prostate Cancer: Myth or Reality?

BACKGROUND

prostate-specific membrane antigen (PSMA) ligand PET has been recently incorporated into international guidelines for several different indications in prostate cancer (PCa) patients. However, there are still some open questions regarding the role of PSMA ligand PET in castration-resistant prostate cancer (CRPC). The aim of this work is to assess the clinical value of PSMA ligand PET/CT in patients with CRPC.

RESULTS

PSMA ligand PET has demonstrated higher detection rates in comparison to conventional imaging and allows for a significant reduction in the number of M0 CRPC patients. However, its real impact on patients' prognosis is still an open question. Moreover, in CRPC patients, PSMA ligand PET presents some sensitivity and specificity limitations. Due to its heterogeneity, CRPC may present a mosaic of neoplastic clones, some of which could be PSMA-/FDG+, or vice versa. Likewise, unspecific bone uptake (UBU) and second primary neoplasms (SNPs) overexpressing PSMA in the neoangiogenic vessels represent potential specificity issues. Integrated multi-tracer imaging (PSMA ligand and [18F]FDG PET) together with a multidisciplinary discussion could allow for reaching the most accurate evaluation of each patient from a precision medicine point of view.

Evaluating the value of 18F-PSMA-1007 PET/CT in the detection and identification of prostate cancer using histopathology as the standard

BACKGROUND

Prostate-specific membrane antigen (PSMA) PET/CT is a highly regarded radionuclide imaging modality for prostate cancer (PCa). This study aimed to evaluate the diagnostic performance of 18F-PSMA-1007 PET/CT in detecting intraprostatic lesions of PCa using radical prostatectomy (RP) specimens as a reference standard and to establish an optimal maximum standardized uptake value (SUVmax) cutoff for distinguishing between PCa and non-PCa lesions.

METHODS

We retrospectively collected 117 patients who underwent 18F-PSMA-1007 PET/CT before RP. The uptake of the index tumor and contralateral non-PCa lesion was assessed. Histopathology of RP specimens was used as the gold standard. Kappa test was used to evaluate the consistency of preoperative PSMA PET/CT staging and postoperative pathological staging. Finally, an SUVmax cutoff value was identified by receiver operating characteristic (ROC) curve analysis to distinguish PCa lesions from non-PCa lesions. A prospective cohort including 76 patients was used to validate the results.

RESULTS

The detection rate of 18F-PSMA-1007 PET/CT for prostate cancer was 96.6% (113/117). 18F-PSMA-1007 had a sensitivity of 91.2% and a positive predictive value (PPV) of 89.8% for the identification of intraprostatic lesions. The consistency test (Kappa = 0.305) indicated poor agreement between the pathologic T-stage and PSMA PET/CT T-stage. Based on ROC curve analysis, the appropriate SUVmax to diagnose PCa lesions was 8.3 (sensitivity of 71.3% and specificity 96.8%) with an area under the curve (AUC) of 0.93 (P < 0.001). This SUVmax cutoff discriminated PCa lesions from non-PCa lesions with a sensitivity of 74.4%, a specificity of 95.8% in the prospective validation group.

CONCLUSIONS

18F-PSMA-1007 PET/CT demonstrated excellent performance in detecting PCa. An optimal SUVmax threshold (8.3) could be utilized to identify lesions of PCa by 18F-PSMA-1007 PET/CT.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04521894, Registered: August 17, 2020.

PSMA hybrid imaging in prostate cancer - current applications and perspectives

BACKGROUND

Prostate cancer (PCa) is the most common malignancy in men and the second most common tumor-associated cause of death in the male population in Germany. Prostate-specific membrane antigen (PSMA)-targeted hybrid imaging using positron emission tomography (PET) in combination with CT or MRI represents a comparably new method that gained increasing importance in the diagnostic process of PCa in recent years.

METHOD

Current applications of PSMA hybrid imaging were summarized according to the German and European guidelines on PCa. New developments were elaborated based on a literature review of PubMed conducted in 10/22.

RESULTS

PSMA-PET/CT demonstrated higher detection rates for metastases in high-risk PCa and recurrent PCa after primary therapy than established imaging methods (CT, MRI, and bone scan). Despite promising results from prospective trials in both scenarios and substantial influence on clinical decision making, data regarding the influence of PSMA-PET on PCa-specific and overall survival are still lacking. Hence, PSMA PET/CT is recommended with a "weak" strength rating in most situations. However, its importance in new treatment options like metastasis-directed therapy or PSMA-radioligand therapy expands the scope of PSMA-PET in the clinical routine.

CONCLUSION

PSMA-targeting hybrid imaging represents the most sensitive diagnostic test in several stages of PCa and allows the development of new treatment strategies. Prospective studies are needed to evaluate the influence of PSMA-PET on patient survival.

KEY POINTS

· PSMA-PET/CT is superior to conventional imaging in the primary staging of high-risk prostate cancer.. · PSMA hybrid imaging can detect metastases in patients with biochemical recurrence at low PSA values.. · Clinical decision making is frequently influenced by results of PSMA-PET/CT..

CITATION FORMAT

· Koehler D, Berliner C, Shenas F et al. PSMA hybrid imaging in prostate cancer - current applications and perspectives. Fortschr Röntgenstr 2023; 195: 1001 - 1008.

Diagnostic and therapeutic impact of PET/CT with 18F-DCFPyL versus 18F-Fluorocholine in initial staging of intermediate-/high-risk prostate cancer: a pilot study

AIM

To assess the diagnostic and therapeutic impact of PET/CT with 18F-DCFPyL with respect to 18F-Fluorocholine in initial staging of intermediate-/high-risk prostate cancer (PCa).

MATERIAL AND METHODS

Patients with recent diagnosis of intermediate-/high-risk PCa without androgen deprivation therapy and previous 18F-Fluorocholine-PET/CT (negative for extraprostatic disease or with oligometastatic disease) were referred to 18F-DCFPyL-PET/CT. Patients' disease characteristic as grade group, D'Amico risk category (intermediate/high), prostate-specific antigen (PSA) closest to PET/CTs and its kinetics were obtained. The overall detection rate (DR) and molecular imaging TNM (miTNM) stage according to the prostate cancer molecular imaging standardized evaluation (PROMISE) criteria were assessed for both radiotracers, and their concordance (Kappa coefficient) was analyzed. The diagnostic and therapeutic impact of 18F-DCFPyL with respect to 18F-Fluorocholine was evaluated.

RESULTS

Fifty-eight patients were analyzed (84.5% high-risk). 18F-Fluorocholine showed a higher DR than 18F-DCFPyL of prostate gland involvement (100% versus 93.1%) and pelvic node disease (37.9% versus 31%; k = 0.436, p = 0.001). On the other hand, 18F-DCFPyL-PET/CT showed a higher DR of metastatic disease than 18F-Fluorocholine-PET/CT, 9/58 patients (15.5%): 3 M1a, 5 M1b and 1 M1c) versus 5/58 (8.6%) patients: 1 M1a and 4 M1b), k = 0.426; p = 0.001. No significant association was found between clinical characteristics (grade group, risk category, PSA level and kinetic) and 18F-Fluorocholine or 18F-DCFPyL results. The results of 18F-DCFPyL-PET/CT modified the previously planned treatment compared to 18F-Fluorocholine-PET/CT in 13 patients (22.4%).

CONCLUSIONS

18F-Fluorocholine and 18F-DCFPyL PET/CT showed a similar DR of prostate gland and lymph node involvement, although with moderate concordance for the latter. 18F-DCFPyL was superior to 18F-Fluorocholine in detecting regional and distant metastasis with a therapeutic impact in one of every five patients.

Diagnostic accuracy of 18F Prostate Specific Membrane Antigen (PSMA) PET-CT radiotracers in staging and restaging of high-risk prostate cancer patients and patients with biochemical recurrence: protocol for an overview of reviews

Background: Correct staging and risk stratification is essential in ensuring prostate cancer patients are offered the most appropriate treatment. Interest has been growing in the use of radiotracers targeting prostate specific membrane antigen (PSMA), including the use of 18F-PSMA PET-CT, as part of the primary staging or restaging of prostate cancer. Preliminary scoping identified a number of relevant systematic reviews and meta-analyses; however, individually, these each appear to look at only part of the picture. An overview of reviews aims to systematically identify, appraise and synthesise multiple systematic reviews, related to a relevant research question or questions. We present a protocol for an overview of reviews, which aims to collate existing evidence syntheses exploring the diagnostic accuracy of 18F-PSMA in staging and restaging of prostate cancer. It also aims to highlight evidence gaps in prostate cancer staging or restaging. Methods: This protocol is reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for systematic review protocols (PRISMA-P). The search strategy will be designed in consultation with a librarian. Searches will be performed in Medline (EBSCO), Embase (Ovid), Google Scholar and the Cochrane Database for Systematic Reviews, supplemented by a targeted grey literature search, forward citation searching and searching reference lists of included reviews. No language or date restrictions will be applied to the eligibility criteria or the search strategy. Title & abstract and full text screening will be performed independently by two reviewers. Data will be extracted by one reviewer and checked in full by a second reviewer. Quality appraisal will be performed using the Risk of Bias in Systematic Reviews (ROBIS) tool independently by two reviewers, and results will be narratively synthesised. Conclusions: This overview of reviews may be of interest to healthcare professionals, academics and health policy decision-makers. Registration: OSF (September 7, 2023).

Interdisciplinary Swiss consensus recommendations on staging and treatment of advanced prostate cancer

The management of prostate cancer is undergoing rapid changes in all disease settings. Novel imaging tools for diagnosis have been introduced, and the treatment of high-risk localized, locally advanced and metastatic disease has changed considerably in recent years. From clinical and health-economic perspectives, a rational and optimal use of the available options is of the utmost importance. While international guidelines list relevant pivotal trials and give recommendations for a variety of clinical scenarios, there is much room for interpretation, and several important questions remain highly debated. The goal of developing a national consensus on the use of these novel diagnostic and therapeutic strategies in order to improve disease management and eventually patient outcomes has prompted a Swiss consensus meeting. Experts from several specialties, including urology, medical oncology, radiation oncology, pathology and nuclear medicine, discussed and voted on questions of the current most important areas of uncertainty, including the staging and treatment of high-risk localized disease, treatment of metastatic hormone-sensitive prostate cancer (mHSPC) and use of new options to treat metastatic castration-resistant prostate cancer (mCRPC).

Advances in high-risk localized prostate cancer: Staging and management

Nearly 15% of individuals with localized prostate cancer are identified as high risk for recurrence and progression of the disease, which is why the correct staging is vital for the definition of correct treatment-also developing novel therapeutic strategies to find a balance between getting better outcomes without sacrificing the quality of life (QoL). In this narrative review, we introduced the current standards of staging and primary treatment of high-risk localized prostate cancer (PCa), based on international guidelines and arguments in the debate, under the light of the most recent literature. It brings essential tools such as PSMA PET/CT and different nomograms (Briganti. MSKCC, Gandaglia) for accurate staging and selecting wisely the definitive therapy. Even though there is a broad discussion over the best local treatment in curative-intent treatment, it looks more important to define which patient profile would adapt correctly to every different treatment, highlighting the benefits and superior outcomes with multimodal treatment.

Carimas: An Extensive Medical Imaging Data Processing Tool for Research

Carimas is a multi-purpose medical imaging data processing tool, which can be used to visualize, analyze, and model different medical images in research. Originally, it was developed only for positron emission tomography data in 2009, but the use of this software has extended to many other tomography imaging modalities, such as computed tomography and magnetic resonance imaging. Carimas is especially well-suited for analysis of three- and four-dimensional image data and creating polar maps in modeling of cardiac perfusion. This article explores various parts of Carimas, including its key features, program structure, and application possibilities.

Deep Learning for Medical Image-Based Cancer Diagnosis

(1) Background: The application of deep learning technology to realize cancer diagnosis based on medical images is one of the research hotspots in the field of artificial intelligence and computer vision. Due to the rapid development of deep learning methods, cancer diagnosis requires very high accuracy and timeliness as well as the inherent particularity and complexity of medical imaging. A comprehensive review of relevant studies is necessary to help readers better understand the current research status and ideas. (2) Methods: Five radiological images, including X-ray, ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI), positron emission computed tomography (PET), and histopathological images, are reviewed in this paper. The basic architecture of deep learning and classical pretrained models are comprehensively reviewed. In particular, advanced neural networks emerging in recent years, including transfer learning, ensemble learning (EL), graph neural network, and vision transformer (ViT), are introduced. Five overfitting prevention methods are summarized: batch normalization, dropout, weight initialization, and data augmentation. The application of deep learning technology in medical image-based cancer analysis is sorted out. (3) Results: Deep learning has achieved great success in medical image-based cancer diagnosis, showing good results in image classification, image reconstruction, image detection, image segmentation, image registration, and image synthesis. However, the lack of high-quality labeled datasets limits the role of deep learning and faces challenges in rare cancer diagnosis, multi-modal image fusion, model explainability, and generalization. (4) Conclusions: There is a need for more public standard databases for cancer. The pre-training model based on deep neural networks has the potential to be improved, and special attention should be paid to the research of multimodal data fusion and supervised paradigm. Technologies such as ViT, ensemble learning, and few-shot learning will bring surprises to cancer diagnosis based on medical images.

The new bone WB-SPECT/CT: hybrid, from head-to-toe and digital! Is it worth the effort?

INTRODUCTION

A bone scan (BS) plays a pivotal role in many oncological and non-oncological conditions. The planar BS is characterized by high sensitivity but low specificity. With respect to planar imaging, the implementation of single-photon emission computed tomography (SPECT) has allowed increased image contrast and more accurate tracer localization.

AREAS COVERED

Recent technological innovations in the field of BS are treated, with a particular focus on multi-field-of-view devices allowing to cover the entire scan length with a 3D acquisition (WB-SPECT/CT). In addition, the applications of cadmium zinc telluride/CzT detectors capable of converting gamma photons directly into electrical impulses (i.e. 'digital SPECT') are discussed.

EXPERT OPINION

Initial clinical experiences indicate that WB-SPECT/CT is characterized by higher sensitivity, diagnostic accuracy, and increased confidence in image interpretation with respect to the 'old-fashioned' BS (planar images with or without a single field-of-view SPECT). Furthermore, CzT-based detectors, thanks to their superior sensitivity, might be helpful to implement fast acquisition protocols. Further studies are needed to better define the clinical impact of bone CzT WB-SPECT/CT on patients' management and outcome, as well as its cost-benefit ratio.

Literature review: Imaging in prostate cancer

Imaging plays an increasingly important role in the detection and characterization of prostate cancer (PC). This review summarizes the key conventional and advanced imaging modalities including multiparametric magnetic resonance imaging (MRI) and positron emission tomography (PET) imaging and tries to instruct clinicians in finding the best image modality depending on the patient`s PC-stage. We aim to give an overview of the different image modalities and their benefits and weaknesses in imaging PC. Emphasis is put on primary prostate cancer detection and staging as well as on recurrent and castration resistant prostate cancer. Results from studies using various imaging techniques are discussed and compared. For the different stages of PC, advantages and disadvantages of the different imaging modalities are discussed. Moreover, this review aims to give an outlook about upcoming, new imaging modalities and how they might be implemented in the future into clinical routine. Imaging patients suffering from PC should aim for exact diagnosis, accurate detection of PC lesions and should mirror the true tumor burden. Imaging should lead to the best patient treatment available in the current PC-stage and should avoid unnecessary therapeutic interventions. New image modalities such as long axial field of view PET/CT with photon-counting CT and radiopharmaceuticals like androgen receptor targeting radiopharmaceuticals open up new possibilities. In conclusion, PC imaging is growing and each image modality is aiming for improvement.

Delayed Imaging Improves Lesion Detectability in [99mTc]Tc-PSMA-I&S SPECT/CT in Recurrent Prostate Cancer

Our objective was to compare the ability to detect histopathologically confirmed lymph node metastases by early and delayed [^99mTc]Tc-PSMA-I&S SPECT/CT in early biochemically recurrent prostate cancer. Methods: We retrospectively analyzed 222 patients selected for radioguided surgery using [^99mTc]Tc-PSMA-I&S SPECT/CT at different time points after injection (≤4 h and >15 h). In total, 386 prostate-specific membrane antigen (PSMA) PET predetermined lesions were analyzed on SPECT/CT using a 4-point scale, and the results were compared between early and late imaging groups, with uni- and multivariate analyses performed including prostate-specific antigen, injected [^99mTc]Tc-PSMA-I&S activity, Gleason grade group, initial TNM stage, and, stratified by size, PSMA PET/CT-positive lymph nodes. PSMA PET/CT findings served as the standard of reference. Results: [^99mTc]Tc-PSMA-I&S SPECT/CT had a significantly higher positivity rate for detecting lesions in the late than the early imaging group (79%, n = 140/178, vs. 27%, n = 12/44 [P < 0.05] on a patient basis; 60%, n = 195/324, vs. 21%, n = 13/62 [P < 0.05] on a lesion basis). Similar positivity rates were found when lesions were stratified by size. Multivariate analysis found that SUV_max on PSMA PET/CT and the uptake time of [^99mTc]Tc-PSMA-I&S were independent predictors for lesion detectability on SPECT/CT. Conclusion: Late imaging (>15 h after injection) should be preferred when [^99mTc]Tc-PSMA-I&S SPECT/CT is used for lesion detection in early biochemical recurrence of prostate cancer. However, the performance of PSMA SPECT/CT is clearly inferior to that of PSMA PET/CT.

Management of Patients with Advanced Prostate Cancer. Part I: Intermediate-/High-risk and Locally Advanced Disease, Biochemical Relapse, and Side Effects of Hormonal Treatment: Report of the Advanced Prostate Cancer Consensus Conference 2022

BACKGROUND

Innovations in imaging and molecular characterisation and the evolution of new therapies have improved outcomes in advanced prostate cancer. Nonetheless, we continue to lack high-level evidence on a variety of clinical topics that greatly impact daily practice. To supplement evidence-based guidelines, the 2022 Advanced Prostate Cancer Consensus Conference (APCCC 2022) surveyed experts about key dilemmas in clinical management.

OBJECTIVE

To present consensus voting results for select questions from APCCC 2022.

DESIGN, SETTING, AND PARTICIPANTS

Before the conference, a panel of 117 international prostate cancer experts used a modified Delphi process to develop 198 multiple-choice consensus questions on (1) intermediate- and high-risk and locally advanced prostate cancer, (2) biochemical recurrence after local treatment, (3) side effects from hormonal therapies, (4) metastatic hormone-sensitive prostate cancer, (5) nonmetastatic castration-resistant prostate cancer, (6) metastatic castration-resistant prostate cancer, and (7) oligometastatic and oligoprogressive prostate cancer. Before the conference, these questions were administered via a web-based survey to the 105 physician panel members ("panellists") who directly engage in prostate cancer treatment decision-making. Herein, we present results for the 82 questions on topics 1-3.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Consensus was defined as ≥75% agreement, with strong consensus defined as ≥90% agreement.

RESULTS AND LIMITATIONS

The voting results reveal varying degrees of consensus, as is discussed in this article and shown in the detailed results in the Supplementary material. The findings reflect the opinions of an international panel of experts and did not incorporate a formal literature review and meta-analysis.

CONCLUSIONS

These voting results by a panel of international experts in advanced prostate cancer can help physicians and patients navigate controversial areas of clinical management for which high-level evidence is scant or conflicting. The findings can also help funders and policymakers prioritise areas for future research. Diagnostic and treatment decisions should always be individualised based on patient and cancer characteristics (disease extent and location, treatment history, comorbidities, and patient preferences) and should incorporate current and emerging clinical evidence, therapeutic guidelines, and logistic and economic factors. Enrolment in clinical trials is always strongly encouraged. Importantly, APCCC 2022 once again identified important gaps (areas of nonconsensus) that merit evaluation in specifically designed trials.

PATIENT SUMMARY

The Advanced Prostate Cancer Consensus Conference (APCCC) provides a forum to discuss and debate current diagnostic and treatment options for patients with advanced prostate cancer. The conference aims to share the knowledge of international experts in prostate cancer with health care providers and patients worldwide. At each APCCC, a panel of physician experts vote in response to multiple-choice questions about their clinical opinions and approaches to managing advanced prostate cancer. This report presents voting results for the subset of questions pertaining to intermediate- and high-risk and locally advanced prostate cancer, biochemical relapse after definitive treatment, advanced (next-generation) imaging, and management of side effects caused by hormonal therapies. The results provide a practical guide to help clinicians and patients discuss treatment options as part of shared multidisciplinary decision-making. The findings may be especially useful when there is little or no high-level evidence to guide treatment decisions.

Safety and efficacy of MRI-guided transurethral ultrasound ablation for radiorecurrent prostate cancer in the presence of gold fiducial markers

BACKGROUND

Safety and efficacy of ultrasound prostate ablation for radiorecurrent prostate cancer (PCa) in the presence of gold fiducial markers has not been previously reported.

PURPOSE

To evaluate safety, functional, and early-stage oncological outcomes for patients with gold fiducial markers undergoing salvage magnetic resonance imaging (MRI)-guided transurethral ultrasound ablation (sTULSA) for radiorecurrent PCa.

MATERIAL AND METHODS

Data were acquired from an ethics-approved, single-center phase-1 study. Eight patients with 18 total gold fiducial markers inside the planned treatment volume were identified. MRI controls were performed at three and 12 months, followed by PSMA-PET-CT imaging and biopsies at 12 months. A control cohort of 13 patients who underwent sTULSA without markers were also identified for safety profile comparison. Adverse events were reported using the Clavien-Dindo classification, and questionnaires including EPIC-26, IPSS, and IIEF-5 were collected.

RESULTS

Of 18 markers, 2 (11%) were directly responsible for poor ultrasound penetration. However, there were no local recurrences at 12 months. PSA, prostate volume, and non-perfused volume all decreased over time. At 12 months, 11/18 (61%) of fiducial markers had disappeared via sloughing. The adverse event profile was similar between both patient cohorts, and when controlled for ablation type, no statistical difference in functional outcomes between the two cohorts was observed.

CONCLUSION

Patients with radiorecurrent PCa with intraprostatic gold fiducial markers can be successfully treated with TULSA. The early-stage efficacy of sTULSA for patients with intraprostatic gold markers is encouraging and the safety profile is unaffected by marker presence.

Flare on [18F]PSMA-1007 PET/CT after short-term androgen deprivation therapy and its correlation to FDG uptake: possible marker of tumor aggressiveness in treatment-naïve metastatic prostate cancer patients

PURPOSE

Short-term androgen deprivation therapy (ADT) is known to increase heterogeneously prostate-specific membrane antigen (PSMA) expression. This phenomenon might indicate the potential of cancer lesions to respond to ADT. In this prospective study, we evaluated the flare on [18F]PSMA-1007 PET/CT after ADT in metastatic prostate cancer (PCa). Given that aggressive PCa tends to display FDG uptake, we particularly investigated whether the changes in PSMA uptake might correlate with glucose metabolism.

METHODS

Twenty-five men with newly diagnosed treatment-naïve metastatic PCa were enrolled in this prospective registered clinical trial. All the patients underwent [18F]PSMA-1007 PET/CT immediately before and 3-4 weeks after ADT initiation (degarelix). Before ADT, [18F]FDG PET/CT was also performed. Standardized uptake values (SUV)max of primary and metastatic lesions were calculated in all PET scans. Serum PSA and testosterone blood samples were collected before the two PSMA PET scans. The changes in PSMA uptake after ADT were represented as ΔSUVmax.

RESULTS

All the patients reached castration levels of testosterone at the time of the second [18F]PSMA-1007 PET/CT. Overall, 57 prostate, 314 lymph nodes (LN), and 406 bone lesions were analyzed. After ADT, 104 (26%) bone, 33 (11%) LN, and 6 (11%) prostate lesions showed an increase (≥ 20%) in PSMA uptake, with a median ΔSUVmax of + 50%, + 60%, and + 45%, respectively. Among the lesions detected at the baseline [18F]PSMA-1007 PET/CT, 63% bone and 46% LN were FDG-positive. In these metastases, a negative correlation was observed between the PSMA ΔSUVmax and FDG SUVmax (p < 0.0001). Moreover, a negative correlation between the ΔSUVmax and the decrease in serum PSA after ADT was noted (p < 0.0001).

CONCLUSIONS

A heterogeneous increase in PSMA uptake after ADT was detected, most evidently in bone metastases. We observed a negative correlation between the PSMA flare and the intensity of glucose uptake as well as the decrease of serum PSA, suggesting that lesions presenting with such flare might potentially be less aggressive.

TRIAL REGISTRATION

NCT03876912, registered 15 March 2019.

Using PSMA imaging for prognostication in localized and advanced prostate cancer

The use of prostate-specific membrane antigen (PSMA)-directed applications in modern prostate cancer management has evolved rapidly over the past few years, helping to establish new treatment pathways and provide further insights into prostate cancer biology. However, the prognostic implications of PSMA-PET have not been studied systematically, owing to rapid clinical implementation without long follow-up periods to determine intermediate-term and long-term oncological outcomes. Currently available data suggest that traditional prognostic factors and survival outcomes are associated with high PSMA expression (both according to immunohistochemistry and PET uptake) in men with localized and biochemically recurrent disease. Treatment with curative intent (primary and/or salvage) often fails when PSMA-positive metastases are present; however, the sensitivity of PSMA-PET in detecting all metastases is poor. Low PSMA-PET uptake in recurrent disease is a favourable prognostic factor; however, it can be associated with poor prognosis in conjunction with high ¹⁸F-fluorodeoxyglucose uptake in metastatic castration-resistant prostate cancer. Clinical trials embedding PSMA-PET for guiding management with reliable oncological outcomes are needed to support ongoing clinical use.

Recurrent Prostate Cancer Diagnostics with 18F-PSMA-1007 PET/CT: A Systematic Review of the Current State

BACKGROUND

Early diagnosis of recurrent prostate cancer is a cornerstone for further adequate therapy planning. Therefore, clinical practice and research still focuses on diagnostic tools that can detect prostate cancer in early recurrence when it is undetectable in conventional diagnostic imaging. ¹⁸F-PSMA-1007 PET/CT is a novel method to evaluate patients with biochemical recurrent PCa. The aim of this review was to evaluate the role of ¹⁸F-PSMA-1007 PET/CT in prostate cancer local recurrence, lymph node metastases and bone metastases detection.

METHODS

Original studies, reviews and five meta-analyses were included in this article. A total of 70 studies were retrieved, 31 were included in the study.

RESULTS

All patients described in the studies underwent ¹⁸F-PSMA-1007 PET/CT. The administered ¹⁸F-PSMA-1007 individual dose ranged from 159 ± 31 MBq to 363.93 ± 69.40 MBq. Results showed that ¹⁸F-PSMA-1007 PET/CT demonstrates a good detection rate in recurrent prostate cancer.

CONCLUSIONS

¹⁸F-PSMA-1007 PET/CT appears to achieve reliable performance in detecting recurrent prostate cancer. The high detection rate of ¹⁸F-PSMA-1007 PET/CT in recurrent prostate cancer was confirmed, especially in local recurrence and small lymph nodes with non-specific characteristics on conventional diagnostic imaging methods. However, several authors emphasize some limitations for this tracer-for example, non-specific uptake in bone lesions that can mimic bone metastases.

Detection of prostate cancer bone metastases with fast whole-body 99mTc-HMDP SPECT/CT using a general-purpose CZT system

BACKGROUND

We evaluated the effects of acquisition time, energy window width, and matrix size on the image quality, quantitation, and diagnostic performance of whole-body ^99mTc-HMDP SPECT/CT in the primary metastasis staging of prostate cancer.

METHODS

Thirty prostate cancer patients underwent ^99mTc-HMDP SPECT/CT from the top of the head to the mid-thigh using a Discovery NM/CT 670 CZT system with list-mode acquisition, 50-min acquisition time, 15% energy window width, and 128 × 128 matrix size. The acquired list-mode data were resampled to produce data sets with shorter acquisition times of 41, 38, 32, 26, 20, and 16 min, narrower energy windows of 10, 8, 6, and 4%, and a larger matrix size of 256 × 256. Images were qualitatively evaluated by three experienced nuclear medicine physicians and quantitatively evaluated by noise, lesion contrast and SUV measurements. Diagnostic performance was evaluated from the readings of two experienced nuclear medicine physicians in terms of patient-, region-, and lesion-level sensitivity and specificity.

RESULTS

The originally acquired images had the best qualitative image quality and lowest noise. However, the acquisition time could be reduced to 38 min, the energy window narrowed to 8%, and the matrix size increased to 256 × 256 with still acceptable qualitative image quality. Lesion contrast and SUVs were not affected by changes in acquisition parameters. Acquisition time reduction had no effect on the diagnostic performance, as sensitivity, specificity, accuracy, and area under the receiver-operating characteristic curve were not significantly different between the 50-min and reduced acquisition time images. The average patient-level sensitivities of the two readers were 88, 92, 100, and 96% for the 50-, 32-, 26-, and 16-min images, respectively, and the corresponding specificities were 78, 84, 84, and 78%. The average region-level sensitivities of the two readers were 55, 58, 59, and 56% for the 50-, 32-, 26-, and 16-min images, respectively, and the corresponding specificities were 95, 98, 96, and 95%. The number of equivocal lesions tended to increase as the acquisition time decreased.

CONCLUSION

Whole-body ^99mTc-HMDP SPECT/CT can be acquired using a general-purpose CZT system in less than 20 min without any loss in diagnostic performance in metastasis staging of high-risk prostate cancer patients.

Preoperative prediction of pelvic lymph nodes metastasis in prostate cancer using an ADC-based radiomics model: comparison with clinical nomograms and PI-RADS assessment

PURPOSE

To develop and test radiomics models based on manually corrected or automatically gained masks on ADC maps for pelvic lymph node metastasis (PLNM) prediction in patients with prostate cancer (PCa).

METHODS

A primary cohort of 474 patients with PCa who underwent prostate mpMRI were retrospectively enrolled for PLNM prediction between January 2017 and January 2020. They were then randomly split into training/validation (n = 332) and test (n = 142) groups for model development and internal testing. Four radiomics models were developed using four masks (manually corrected/automatic prostate gland and PCa lesion segmentation) based on the ADC maps using the primary cohort. Another cohort of 128 patients who underwent radical prostatectomy (RP) with extended pelvic lymph node dissection (ePLND) for PCa was used as the testing cohort between February 2020 and October 2021. The performance of the models was evaluated in terms of discrimination and clinical usefulness using the area under the curve (AUC) and decision curve analysis (DCA). The optimal radiomics model was further compared with Memorial Sloan Kettering Cancer Center (MSKCC) and Briganti 2017 nomograms, and PI-RADS assessment.

RESULTS

17 (13.28%) Patients with PLNM were included in the testing cohort. The radiomics model based on the mask of automatically segmented prostate obtained the highest AUC among the four radiomics models (0.73 vs. 0.63 vs. 0.70 vs. 0.56). Briganti 2017, MSKCC nomograms, and PI-RADS assessment-yielded AUCs of 0.69, 0.71, and 0.70, respectively, and no significant differences were found compared with the optimal radiomics model (P = 0.605-0.955).

CONCLUSION

The radiomics model based on the mask of automatically segmented prostate offers a non-invasive method to predict PLNM for patients with PCa. It shows comparable accuracy to the current MKSCC and Briganti nomograms.

The Detection Performance of 18 F-Prostate-Specific Membrane Antigen-1007 PET/CT in Primary Prostate Cancer : A Systemic Review and Meta-analysis

BACKGROUND

Multiple tools are now available to determine the requirement for a biopsy to diagnose prostate cancer, and PET/CT with radiolabeled prostate-specific membrane antigen (PSMA)-targeting radiotracers has been recommended for detecting primary prostate cancer. Particularly, the radiotracer 18 F-PSMA-1007 was found to be more favorable for primary tumors compared with other PSMA-targeting radiotracers because of its low clearance via the urinary tract and better image resolution. Thus, we performed a systematic review and meta-analysis to more accurately evaluate the detection performance of 18 F-PSMA-1007 PET/CT in primary prostate cancer patients.

METHODS

An update on the databases of PubMed/MEDLINE, EMBASE, and Cochrane Library for comprehensive literature search was performed on September 30, 2021. The pooling detection rate was calculated on a per-patient basis. The pooling median of the SUV max was analyzed from the included studies. Furthermore, the positive predictive value of 18 F-PSMA-1007 PET/CT with pathologic lesions was analyzed using the criterion standard.

RESULTS

Twelve studies (540 patients total) were included in the meta-analysis. The overall pooling detection rate of 18 F-PSMA-1007 per patient was 94%, and the pooling median of SUV max located at the intraprostate tumor was 16 (range, 3.7-77.7). The positive predictive value of 18 F-PSMA-1007 per lesion with histopathological validation was 0.90, detecting regional lymph node metastasis was 0.94, and detecting localized prostatic tumors was 0.84.

CONCLUSIONS

In the current meta-analysis, we revealed the excellent performance of 18 F-PSMA-1007 to detect localized prostatic tumor lesions and regional lymph node metastasis. Moreover, the uptake of localized tumors in primary prostate cancer was nearly liver uptake and may be considered a suspicious malignancy if it was equal to or greater than the liver uptake.

The Role of PSMA PET/CT in the Primary Diagnosis and Follow-Up of Prostate Cancer-A Practical Clinical Review

Simple Summary

The combination of positron emission tomography (PET)-diagnostics with ligands binding to the prostate-specific membrane antigen (PSMA) has been a diagnostic milestone in the situation of biochemical recurrence of prostate cancer and is gaining importance in primary diagnostics, providing a highly specific and sensitive diagnostic method in various clinical situations. However, the clinical application of this method requires a comprehensive knowledge of its advantages and disadvantages, potential pitfalls and influencing factors. This review aims to provide a practical clinical review of the currently available background data on PSMA PET/CT, as well as the clinical implications. Although a large amount of data already exist, a thorough analysis is complicated by study heterogeneity, showing the need for future systematic and prospective research.

Abstract

The importance of PSMA PET/CT in both primary diagnostics and prostate cancer recurrence has grown steadily since its introduction more than a decade ago. Over the past years, a vast amount of data have been published on the diagnostic accuracy and the impact of PSMA PET/CT on patient management. Nevertheless, a large heterogeneity between studies has made reaching a consensus difficult; this review aims to provide a comprehensive clinical review of the available scientific literature, covering the currently known data on physiological and pathological PSMA expression, influencing factors, the differences and pitfalls of various tracers, as well as the clinical implications in initial TNM-staging and in the situation of biochemical recurrence. This review has the objective of providing a practical clinical overview of the advantages and disadvantages of the examination in various clinical situations and the body of knowledge available, as well as open questions still requiring further research.

Detection rate of fluorine-18 prostate-specific membrane antigen-1007 PET/CT for prostate cancer in primary staging and biochemical recurrence with different serum PSA levels: A systematic review and meta-analysis

Background

We performed a systematic review and meta-analysis to evaluate the detection rate (DR) of fluoro-prostate-specific membrane antigen (¹⁸F-PSMA-1007) PET/CT in patients with different serum prostate-specific antigen (PSA) levels in the setting of primary staging of prostate cancer (PCa) or biochemically recurring PCa.

Methods

A comprehensive electronic literature search of the PubMed, Embase, and Cochrane Library databases was conducted in accordance with the PRISMA statement. This study was registered in the PROSPERO database (registration number: CRD42022331595). We calculated the DR of ¹⁸F-PSMA-1007 PET/CT in PCa.

Results

The final analysis included 15 studies that described 1,022 patients and 2,034 lesions with ¹⁸F-PSMA-1007 PET/CT in PCa. The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in primary staging ranged from 90% to 100%, with a pooled estimate of 94% (95% CI: 92%–96%). The DR of ¹⁸F-PSMA-1007 PET/CT in patients with PCa in BCR ranged from 47% to 100%, with a pooled estimate of 86% (95% CI: 76%–95%). The DRs of PSA levels >2.0, 1.1–2.0, 0.51–1.0, and ≤0.5 ng/ml detected by ¹⁸F-PSMA-1007 PET/CT in a patient-based analysis were 97% (95% CI: 93%–99%), 95% (95% CI: 88%–99%), 79% (95% CI: 68%–88%), and 68% (95% CI: 58%–78%), respectively.

Conclusion

This meta-analysis concluded that ¹⁸F-PSMA-1007 PET/CT had a high application value for prostate cancer, including primary tumors and biochemical recurrence. The DR of ¹⁸F-PSMA-1007 PET/CT was slightly higher in primary prostate tumors than in biochemical recurrence.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022331595.

The Continuum of Metastatic Prostate Cancer: Interpreting PSMA PET Findings in Recurrent Prostate Cancer

Conventional imaging has been the standard imaging modality for assessing prostate cancer recurrence and is utilized to determine treatment response to therapy. Molecular imaging with PSMA PET-CT has proven to be more accurate, sensitive, and specific at identifying pelvic or distant metastatic disease, resulting in earlier diagnosis of advanced disease. Since advanced disease may not be seen on conventional imaging, due to its lower sensitivity, but can be identified by molecular imaging, this reveals that metastatic prostate cancer occurs on a continuum from negative PSMA PET-CT and negative conventional imaging to positive PSMA PET-CT and positive conventional imaging. Understanding this continuum, the accuracy of these modalities, and treatment related outcomes based on imaging, will allow the clinician to counsel patients on management. This review will highlight the differences in conventional and molecular imaging in prostate cancer and how PSMA PET-CT can be used for the management of prostate cancer patients in different clinical scenarios, while providing cautionary notes for overtreatment.

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.

Diagnostic value of integrated 18F-PSMA-1007 PET/MRI Compared with that of Biparametric MRI for the detection of Prostate Cancer

Objective

Materials and methods

Results

Conclusion

[Prostate-specific membrane antigen positron emission tomography (PSMA PET) for urologists-when and which tracer?]

BACKGROUND

Prostate-specific membrane antigen positron emission tomography (PSMA PET) is increasingly replacing conventional imaging for staging of prostate cancer. A major challenge is its appropriate use and correct interpretation.

OBJECTIVES

How and when is PSMA PET used in patient care to optimally direct therapy?

MATERIALS AND METHODS

Systematic presentation and discussion of the current state of knowledge, guidelines and expert knowledge on PSMA PET with a summary of ongoing studies.

CONCLUSION

PSMA PET is the new standard for systemic staging of prostate cancer, enabling precision patient care with novel local, oligometastatic, and systemic treatment approaches.

Focal PSMA-Positive Pleural Lesion in a Patient With Stage II Prostate Carcinoma

ABSTRACT

A 70-year-old man with histopathologically proven prostate carcinoma (Gleason, 5 + 5; prostate-specific antigen level, 6.2 μg/mL) was referred for an 18F-PSMA-1007 PET/CT scan. The scan revealed bilateral PSMA uptake in the prostate, representing the primary tumor, but no evidence of PSMA-positive lymph nodes. However, a left-sided ventral pleural thickening showed focal PSMA uptake. Lesion biopsy showed no signs of malignancy, and prostatectomy was performed. The 1-year follow-up CT thorax showed growth of approximately 20% of the pleural lesion. Subsequently, video-assisted thoracic surgery of the lesion was performed. Histopathology showed a solitary fibrous tumor, a rare mesenchymal tumor.

Comparison of reprojected bone SPECT/CT and planar bone scintigraphy for the detection of bone metastases in breast and prostate cancer

OBJECTIVE

The aim of this study was to compare reprojected bone SPECT/CT (RBS) against planar bone scintigraphy (BS) in the detection of bone metastases in breast and prostate cancer patients.

METHODS

Twenty-six breast and 105 prostate cancer patients with high risk for bone metastases underwent 99mTc-HMDP BS and whole-body SPECT/CT, 1.5-T whole-body diffusion-weighted MRI and 18F-NaF or 18F-PSMA-1007 PET/CT within two prospective clinical trials (NCT01339780 and NCT03537391). Consensus reading of all imaging modalities and follow-up data were used to define the reference standard diagnosis. The SPECT/CT data were reprojected into anterior and posterior views to produce RBS images. Both BS and RBS images were independently double read by two pairs of experienced nuclear medicine physicians. The findings were validated against the reference standard diagnosis and compared between BS and RBS on the patient, region and lesion levels.

RESULTS

All metastatic patients detected by BS were also detected by RBS. In addition, three metastatic patients were missed by BS but detected by RBS. The average patient-level sensitivity of two readers for metastases was 75% for BS and 87% for RBS, and the corresponding specificity was 79% for BS and 39% for RBS. The average region-level sensitivity of two readers was 64% for BS and 69% for RBS, and the corresponding specificity was 96% for BS and 87% for RBS.

CONCLUSION

Whole-body bone SPECT/CT can be reprojected into more familiar anterior and posterior planar images with excellent sensitivity for bone metastases, making additional acquisition of planar BS unnecessary.

Risk of metastatic disease using [18F]PSMA-1007 PET/CT for primary prostate cancer staging

BACKGROUND

Accurate prostate cancer imaging is critical for patient management. Multiple studies have demonstrated superior diagnostic accuracy of [⁶⁸Ga]-PSMA-11 PET/CT over conventional imaging for disease detection, with validated clinical and biochemical predictors of disease detection. More recently [¹⁸F]PSMA-1007 offers theoretical imaging advantages, but there is limited evidence of clinical and biochemical predictors of scan findings in the staging population. This study investigates the association of clinical variables with imaging characteristics among patients who underwent [¹⁸F]PSMA-1007 PET/CT for primary staging of men with histopathologically confirmed prostate carcinoma. A retrospective review of 194 consecutive patients imaged between May 2019 to May 2020 was performed. Association between imaging variables (presence and distribution of metastatic disease, primary tumour SUVmax) and clinical variables (EAU risk criteria) were assessed using descriptive statistics, logistic regression model and ROC analysis.

RESULTS

The median age, PSA level and ISUP grade were 70 years, 10 ng/mL and ISUP grade 3, respectively. There were 36.6% of patients with intermediate-risk and 60.8% of patients with high-risk disease. ISUP grade was associated with the presence of metastasis overall (p = 0.008) as well as regional nodal (p = 0.003), non-regional nodal (p = 0.041) and bone (p = 0.006) metastases. PSA level was associated with metastatic disease overall (p = 0.001), regional (p = 0.001) and non-regional nodal metastases (p = 0.004), but not with bone metastases (p = 0.087). There were too few visceral metastases for meaningful analysis. SUVmax of the primary prostatic tumour was associated with ISUP grade (p = 0.004), PSA level (p < 0.001) and AJCC stage (p = 0.034). PSA > 20 ng/mL and ISUP grade > 3 had a specificity of 85% (95% CI 78-91%) and 60% (95% CI 50-68%) and a sensitivity of 36% (95% CI 25-49%) and 62% (95% CI 49-74%), respectively, for detection of metastatic disease.

CONCLUSION

Metastatic disease according to [¹⁸F]PSMA-1007 PET/CT was associated with ISUP grade and PSA level. This is the largest study using [¹⁸F]PSMA-1007 PET/CT to confirm a positive correlation of PSA level, ISUP grade and stage with primary prostate tumour SUVmax.

Molecular Imaging in Primary Staging of Prostate Cancer Patients: Current Aspects and Future Trends

Accurate primary staging is the cornerstone in all malignancies. Different morphological imaging modalities are employed in the evaluation of prostate cancer (PCa). Regardless of all developments in imaging, invasive histopathologic evaluation is still the standard method for the detection and staging of the primary PCa. Magnetic resonance imaging (MRI) and computed tomography (CT) play crucial roles; however, functional imaging provides additional valuable information, and it is gaining ever-growing acceptance in the management of PCa. Targeted imaging with different radiotracers has remarkably evolved in the past two decades. [111In]In-capromab pendetide scintigraphy was a new approach in the management of PCa. Afterwards, positron emission tomography (PET) tracers such as [11C/18F]choline and [11C]acetate were developed. Nevertheless, none found a role in the primary staging. By introduction of the highly sensitive small molecule prostate-specific membrane antigen (PSMA) PET/CT, as well as recent developments in MRI and hybrid PET/MRI systems, non-invasive staging of PCa is being contemplated. Several studies investigated the role of these sophisticated modalities in the primary staging of PCa, showing promising results. Here, we recapitulate the role of targeted functional imaging. We briefly mention the most popular radiotracers, their diagnostic accuracy in the primary staging of PCa, and impact on patient management.

Comparison of 68Ga-Prostate Specific Membrane Antigen (PSMA) Positron Emission Tomography Computed Tomography (PET-CT) and Whole-Body Magnetic Resonance Imaging (WB-MRI) with Diffusion Sequences (DWI) in the Staging of Advanced Prostate Cancer

Simple Summary

Precise staging is key for the optimal management of advanced prostate cancer. PSMA PET-CT and WB-MRI outperform standard imaging technology for staging high-risk prostate cancer, but direct comparison between both modalities is lacking. The primary endpoint of our study was to compare the diagnostic accuracy of both techniques in the detection of lymph node, bone and visceral metastases against a best valuable comparator (BVC), defined as a consensus adjudication of all lesions on the basis of baseline and follow-up imaging, biological and clinical data and histopathologic confirmation when available. Knowing the diagnostic accuracy of both next generation imaging modalities might influence the diagnostic and therapeutic strategy in prostate cancer by tailoring therapy. However, the impact on treatment and patient outcome of an improved detection of metastases has not been determined yet.

Abstract

Background: Prostate specific membrane antigen (PSMA) positron emission tomography computed tomography (PET-CT) and whole-body magnetic resonance imaging (WB-MRI) outperform standard imaging technology for the detection of metastasis in prostate cancer (PCa). There are few direct comparisons between both modalities. This paper compares the diagnostic accuracy of PSMA PET-CT and WB-MRI for the detection of metastasis in PCa. One hundred thirty-four patients with newly diagnosed PCa (n = 81) or biochemical recurrence after curative treatment (n = 53) with high-risk features prospectively underwent PSMA PET-CT and WB-MRI. The diagnostic accuracy of both techniques for lymph node, skeletal and visceral metastases was compared against a best valuable comparator (BVC). Overall, no significant difference was detected between PSMA PET-CT and WB-MRI to identify metastatic patients when considering lymph nodes, skeletal and visceral metastases together (AUC = 0.96 (0.92–0.99) vs. 0.90 (0.85–0.95); p = 0.09). PSMA PET-CT, however, outperformed WB-MRI in the subgroup of patients with newly diagnosed PCa for the detection of lymph node metastases (AUC = 0.96 (0.92–0.99) vs. 0.86 (0.79–0.92); p = 0.0096). In conclusion, PSMA PET-CT outperforms WB-MRI for the detection of nodal metastases in primary staging of PCa.

Prospective comparison of 18F-PSMA-1007 PET/CT, whole-body MRI and CT in primary nodal staging of unfavourable intermediate- and high-risk prostate cancer

PURPOSE

To prospectively compare 18F-prostate-specific membrane antigen (PSMA)-1007 positron emission tomography (PET)/CT, whole-body magnetic resonance imaging (WBMRI) including diffusion-weighted imaging (DWI) and standard computed tomography (CT), in primary nodal staging of prostate cancer (PCa).

METHODS

Men with newly diagnosed unfavourable intermediate- or high-risk PCa prospectively underwent 18F-PSMA-1007 PET/CT, WBMRI with DWI and contrast-enhanced CT within a median of 8 days. Six readers (two for each modality) independently reported pelvic lymph nodes as malignant, equivocal or benign while blinded to the other imaging modalities. Sensitivity, specificity and accuracy were reported according to optimistic (equivocal lesions interpreted as benign) and pessimistic (equivocal lesions interpreted as malignant) analyses. The reference standard diagnosis was based on multidisciplinary consensus meetings where available histopathology, clinical and follow-up data were used.

RESULTS

Seventy-nine patients completed all the imaging modalities, except for one case of interrupted WBMRI. Thirty-one (39%) patients had pelvic lymph node metastases, which were detected in 27/31 (87%), 14/31 (45%) and 8/31 (26%) patients by 18F-PSMA-1007 PET/CT, WBMRI with DWI and CT, respectively (optimistic analysis). In 8/31 (26%) patients, only 18F-PSMA-1007 PET/CT detected malignant lymph nodes, while the other two imaging modalities were reported as negative. At the patient level, sensitivity and specificity values for 18F-PSMA-1007 PET/CT, WBMRI with DWI and CT in optimistic analysis were 0.87 (95%CI 0.71-0.95) and 0.98 (95%CI 0.89-1.00), 0.37 (95%CI 0.22-0.55) and 0.98 (95%CI 0.89-1.00) and 0.26 (95%CI 0.14-0.43) and 1.00 (95%CI 0.93-1.00), respectively.

CONCLUSION

18F-PSMA-1007 PET/CT showed significantly greater sensitivity in nodal staging of primary PCa than did WBMRI with DWI or CT, while maintaining high specificity.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov ID: NCT03537391.