Diagnostic performance of 68Ga-PSMA PET/CT for identification of aggressive cribriform morphology in prostate cancer with whole-mount sections

Optimising prostate biopsies and imaging for the future-a review

Conventionally, transrectal ultrasound guided prostate biopsy (TRUS-Bx) was the main technique used for the diagnosis of prostate cancer since it was first described in 1989 [1]. However, the PROMIS trial showed that this random, nontargeted approach could miss up to 18% of clinically significant cancer (csPCa) [2]. Furthermore, risk of sepsis post TRUS-Bx can be as high as 2.4% [3]. Understanding the demerits of TR-biopsy have led to the introduction of transperineal prostate biopsy (TP-Bx). The incorporation of mpMRI revolutionized prostate cancer diagnostics, allowing visualization of areas likely to harbor csPCa whilst permitting some men to avoid an immediate biopsy. Furthermore, the advent of prostate specific membrane antigen-positron emission tomography (PSMA-PET) is highly promising, because of its role in primary diagnosis of prostate cancer and its higher diagnostic accuracy over conventional imaging in detecting nodal and metastatic lesions. Our narrative review provides an overview on prostate biopsy techniques and an update on prostate imaging, with particular focus on PSMA-PET.

Molecular Hallmarks of Prostate-specific Membrane Antigen in Treatment-naïve Prostate Cancer

BACKGROUND AND OBJECTIVE

We characterized tumor prostate-specific membrane antigen (PSMA) levels as a reflection of cancer biology and treatment sensitivities for treatment-naïve prostate cancer.

METHODS

We first correlated PSMA positron emission tomography (PET) maximum standardized uptake values (SUVmax) in primary prostate cancer with tumor FOLH1 (PSMA RNA abundance) to establish RNA as a proxy (n = 55). We then discovered and validated molecular pathways associated with PSMA RNA levels in two large primary tumor cohorts. We validated those associations in independent cohorts (18 total; 5684 tumor samples) to characterize the pathways and treatment responses associated with PSMA.

KEY FINDINGS AND LIMITATIONS

PSMA RNA abundance correlates moderately with SUVmax (ρ = 0.41). In independent cohorts, androgen receptor signaling is more active in tumors with high PSMA. Accordingly, patients with high PSMA tumors experienced longer cancer-specific survival when managed with androgen deprivation therapy for biochemical recurrence (adjusted hazard ratio [AHR] 0.54 [0.34-0.87]; n = 174). PSMA low tumors possess molecular markers of resistance to radiotherapy. Consistent with this, patients with high PSMA tumors experience longer time to recurrence following primary radiotherapy (AHR 0.50 [0.28-0.90]; n = 248). In the SAKK09/10 trial (n = 224), patients with high PSMA tumors who were managed with salvage radiotherapy experienced longer time to progression in the 64-Gy arm (restricted mean survival time [RMST] +7.60 [0.05-15.16]), but this effect was mitigated in the 70-Gy arm (RMST 3.52 [-3.30 to 10.33]). Limitations include using PSMA RNA as a surrogate for PET SUVmax.

CONCLUSIONS AND CLINICAL IMPLICATIONS

PSMA levels in treatment-naïve prostate cancer differentiate tumor biology and treatment susceptibilities. These results warrant validation using PET metrics to substantiate management decisions based on imaging.

Preliminary clinical practice of radical prostatectomy without preoperative biopsy

BACKGROUND

At present, biopsy is essential for the diagnosis of prostate cancer (PCa) before radical prostatectomy (RP). However, with the development of prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) and multiparametric magnetic resonance imaging (mpMRI), it might be feasible to avoid biopsy before RP. Herein, we aimed to explore the feasibility of avoiding biopsy before RP in patients highly suspected of having PCa after assessment of PSMA PET/CT and mpMRI.

METHODS

Between December 2017 and April 2022, 56 patients with maximum standardized uptake value (SUVmax) of ≥4 and Prostate Imaging Reporting and Data System (PI-RADS) ≥4 lesions who received RP without preoperative biopsy were enrolled from two tertiary hospitals. The consistency between clinical and pathological diagnoses was evaluated. Preoperative characteristics were compared among patients with different pathological types, T stages, International Society of Urological Pathology (ISUP) grades, and European Association of Urology (EAU) risk groups.

RESULTS

Fifty-five (98%) patients were confirmed with PCa by pathology, including 49 (89%) with clinically significant prostate cancer (csPCa, defined as ISUP grade ≥2 malignancy). One patient was diagnosed with high-grade prostatic intraepithelial neoplasia (HGPIN). CsPCa patients, compared with clinically insignificant prostate cancer (cisPCa) and HGPIN patients, were associated with a higher level of prostate-specific antigen (22.9 ng/mL vs. 10.0 ng/mL, P = 0.032), a lower median prostate volume (32.2 mL vs. 65.0 mL, P = 0.001), and a higher median SUVmax (13.3 vs. 5.6, P <0.001).

CONCLUSIONS

It might be feasible to avoid biopsy before RP for patients with a high probability of PCa based on PSMA PET/CT and mpMRI. However, the diagnostic efficacy of csPCa with PI-RADS ≥4 and SUVmax of ≥4 is inadequate for performing a procedure such as RP. Further prospective multicenter studies with larger sample sizes are necessary to confirm our perspectives and establish predictive models with PSMA PET/CT and mpMRI.

Metabolic imaging across scales reveals distinct prostate cancer phenotypes

Hyperpolarised magnetic resonance imaging (HP-13C-MRI) has shown promise as a clinical tool for detecting and characterising prostate cancer. Here we use a range of spatially resolved histological techniques to identify the biological mechanisms underpinning differential [1-13C]lactate labelling between benign and malignant prostate, as well as in tumours containing cribriform and non-cribriform Gleason pattern 4 disease. Here we show that elevated hyperpolarised [1-13C]lactate signal in prostate cancer compared to the benign prostate is primarily driven by increased tumour epithelial cell density and vascularity, rather than differences in epithelial lactate concentration between tumour and normal. We also demonstrate that some tumours of the cribriform subtype may lack [1-13C]lactate labelling, which is explained by lower epithelial lactate dehydrogenase expression, higher mitochondrial pyruvate carrier density, and increased lipid abundance compared to lactate-rich non-cribriform lesions. These findings highlight the potential of combining spatial metabolic imaging tools across scales to identify clinically significant metabolic phenotypes in prostate cancer.

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.

Advantage of whole-mount histopathology in prostate cancer: current applications and future prospects

BACKGROUND

Whole-mount histopathology (WMH) has been a powerful tool to investigate the characteristics of prostate cancer. However, the latest advancement of WMH was yet under summarization. In this review, we offer a comprehensive exposition of current research utilizing WMH in diagnosing and treating prostate cancer (PCa), and summarize the clinical advantages of WMH and outlines potential on future prospects.

METHODS

An extensive PubMed search was conducted until February 26, 2023, with the search term "prostate", "whole-mount", "large format histology", which was limited to the last 4 years. Publications included were restricted to those in English. Other papers were also cited to contribute a better understanding.

RESULTS

WMH exhibits an enhanced legibility for pathologists, which improved the efficacy of pathologic examination and provide educational value. It simplifies the histopathological registration with medical images, which serves as a convincing reference standard for imaging indicator investigation and medical image-based artificial intelligence (AI). Additionally, WMH provides comprehensive histopathological information for tumor volume estimation, post-treatment evaluation, and provides direct pathological data for AI readers. It also offers complete spatial context for the location estimation of both intraprostatic and extraprostatic cancerous region.

CONCLUSIONS

WMH provides unique benefits in several aspects of clinical diagnosis and treatment of PCa. The utilization of WMH technique facilitates the development and refinement of various clinical technologies. We believe that WMH will play an important role in future clinical applications.

Convoluted Neural Network for Detection of Clinically Significant Prostate Cancer on 68 Ga PSMA PET/CT Delayed Imaging by Analyzing Radiomic Features

Purpose

To assess the utility of convoluted neural network (CNN) in differentiating clinically significant and insignificant prostate cancer in patients with 68 Ga PSMA PET/CT-targeted prostate biopsy-proven prostate cancer.

Methods

In this retrospective study, 142 patients with clinical suspicion of prostate cancer were evaluated who underwent 68 Ga-PSMA PET/CT imaging followed by 68 Ga-PSMA PET/CT-targeted prostate biopsy from the PSMA-avid prostate lesion. Twenty patients with no PSMA-avid lesions were excluded. Local Image Features Extraction (LifeX) software was used to extract radiomic features (RF) from delayed 68 Ga-PSMA PET/CT images of 122 patients. LifeX failed to extract radiomic features in 24 patients, and the remaining 98 were evaluated. RFs were fed to an in-built CNN of the software for computation and results were achieved. Patients with Gleason Score ≥ 7 on histopathology were labeled clinically significant prostate cancer (csPCa). The diagnostic values of radiomic features were evaluated.

Results

The csPCa was revealed in 69/98 (70.4%) patients, and insignificant PCa was noticed in 29/98 (29.6%) patients. The software extracted 124 RF from the delayed 68 Ga-PSMA PET/CT images. The accuracy of the CNN was 80.7% to differentiate clinically significant and clinically insignificant prostate cancer, with an error percentage (E %) of 19.3%. The sensitivity, specificity, positive predictive, and negative predictive values were 90.3%, 57.7%, 83.6%, and 71.4%, respectively, to detect csPCa.

Conclusion

CNN is a feasible pre-biopsy screening tool for identifying clinically significant prostate cancer and can be used as an adjunct in the initial diagnosis and early treatment planning.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13139-023-00832-3.

Is cribriform pattern in prostate biopsy a risk factor for metastatic disease on 68Ga-PSMA-11 PET/CT?

INTRODUCTION

Cribriform growth pattern (CP) in prostate cancer (PCa) has been associated with different unfavourable oncological outcomes. This study addresses if CP in prostate biopsies is an independent risk factor for metastatic disease on PSMA PET/CT.

METHODS

Treatment-naive patients with ISUP GG ≥ 2 staged with 68Ga-PSMA-11 PET/CT diagnosed from 2020 to 2021 were retrospectively enrolled. To test if CP in biopsies was an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT, regression analyses were performed. Secondary analyses were performed in different subgroups.

RESULTS

A total of 401 patients were included. CP was reported in 252 (63%) patients. CP in biopsies was not an independent risk factor for metastatic disease on the 68Ga-PSMA PET/CT (p = 0.14). ISUP grade group (GG) 4 (p = 0.006), GG 5 (p = 0.003), higher PSA level groups per 10 ng/ml until > 50 (p-value between 0.02 and > 0.001) and clinical EPE (p > 0.001) were all independent risk factors. In the subgroups with GG 2 (n = 99), GG 3 (n = 110), intermediate-risk group (n = 129) or the high-risk group (n = 272), CP in biopsies was also not an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT. If the EAU guideline recommendation for performing metastatic screening was applied as threshold for PSMA PET/CT imaging, in 9(2%) patients, metastatic disease was missed, and 18% fewer PSMA PET/CT would have been performed.

CONCLUSION

This retrospective study found that CP in biopsies was not an independent risk factor for metastatic disease on 68Ga-PSMA PET/CT.

The cribriform morphology impairs Gleason 7 prostate cancer lesion detection on multiparametric magnetic resonance imaging

BACKGROUND

Prostate multiparametric magnetic resonance imaging (mpMRI) is a useful tool for the detection of tumor lesions however, some clinically significant lesions are still missed. We determined whether the cribriform pattern has an effect on lesion detection in mpMRI.

METHODS

We reviewed the single-institution database of the patients who underwent mpMRI before radical prostatectomy. We included the patients only with the Gleason 7 final pathology of open radical prostatectomy with curative intent between 2016 and 2021. Prostatectomy mappings according to the 16-sector map and cribriform patterns were re-evaluated by two genitourinary pathologists. Prostate mpMRIs were read by two genitourinary radiologists. If the index and nonindex lesions in pathology mapping were matched with mpMRI as Prostate Imaging Reporting and Data System-3 or higher, it was defined as detectable. We compared the detection rates of lesions with and without cribriform morphology. In regression analysis, we also assessed the factors affecting the detectability of prostate cancer lesions.

RESULTS

A total of 120 patients and 157 lesions were included in our study. While 52 of 83 cribriform pattern positive lesions could be detected in mpMRI, 59 of 74 cribriform pattern negative lesions could be detected (62.7% vs. 79.7%, respectively, p = 0.019). The lesions were also distributed homogeneously according to diameters and analyzed separately. All lesions between 21 and 30 mm with the negative cribriform pattern were detected on mpMRI. However, only 77.8% of cribriform pattern positive lesions between 21 and 30 mm could be detected (p = 0.034). The Higher D'Amico risk group and the absence of cribriform morphology were independent predictors for the lesion detection on mpMRI.

CONCLUSION

The presence of cribriform pattern in Gleason 7 prostate cancer lesions decreases the lesion detection rate of mpMRI.

Reprint of: morphologic spectrum of treatment-related changes in prostate tissue and prostate cancer: an updated review

A wide range of treatment options are available to patients with prostate cancer. Some treatments are standard (currently used) while some are emerging therapies. Androgen deprivation therapy is typically reserved for localized or metastatic prostate cancer not amenable to surgery. Radiation therapy may be offered to individuals for local therapy with curative intent in low- or intermediate-risk disease that may have a high probability of progression on active surveillance or where surgery is not suitable. Focal therapy/ablation treatment is an alternative approach for those who prefer to avoid radical prostatectomy for localized disease of low- or intermediate-risk or as salvage therapy after failed radiation therapy. Chemotherapy and immunotherapy remain under investigation and are currently used for androgen-independent disease or hormone-refractory prostate cancer; however, a better understanding of therapeutic efficacy is needed. Histopathologic changes observed in benign and malignant prostate tissue induced by hormonal therapies and radiation therapy are well described, whereas treatment-related effects secondary to novel therapies continue to be documented although their clinical significance is not absolutely clear. An informed and accurate evaluation of post-treatment prostate specimens requires pathologists with diagnostic acumen and knowledge relating to the histopathologic spectrum associated with each treatment option. In situations when clinical history is lacking, but morphologic features are suggestive of prior treatment, pathologists are encouraged to consult clinical colleagues regarding prior treatment history including details of when treatment was initiated and duration of therapy. This review aims to provide a concise update of current and emerging therapies for prostate cancer, histologic alterations and recommendations on Gleason grading.

Intermediate-risk Prostate Cancer-A Sheep in Wolf's Clothing?

This case-based discussion describes a 65-year-old man newly diagnosed with International Society of Urological Pathology (ISUP) grade 2 prostate cancer (PCa). According to the European Association of Urology classification system, the patient harbors an intermediate-risk cancer. In step-by step discussion, we elaborate guideline-based treatment modalities for intermediate-risk PCa focused on debating active surveillance versus active treatment. Thereby, we discuss the importance of patient characteristics, including age, hereditary factors, life expectancy and comorbidity status, findings of multiparametric magnetic resonance imaging, as well as prostate-specific antigen (PSA) density and PSA kinetics, in predicting the clinical course of the disease. In addition, we focus on cribriform pathology as a predictor of adverse outcomes and critically discuss its relevance in patient management. Lastly, we outline genomic stratification in ISUP 2 cancer as a future tool to predict PCa aggressiveness. PATIENT SUMMARY: Based on current guidelines, patients with intermediate-risk prostate cancer are treated actively or can alternatively undergo an active surveillance approach when favorable risk factors are present. One major issue is to discriminate between patients who benefit from an active therapy approach and those who benefit from a deferred treatment. Therefore, reliable biomarkers and early predictors of disease progression are needed urgently.

Single cell analysis of cribriform prostate cancer reveals cell intrinsic and tumor microenvironmental pathways of aggressive disease

Cribriform prostate cancer, found in both invasive cribriform carcinoma (ICC) and intraductal carcinoma (IDC), is an aggressive histological subtype that is associated with progression to lethal disease. To delineate the molecular and cellular underpinnings of ICC/IDC aggressiveness, this study examines paired ICC/IDC and benign prostate surgical samples by single-cell RNA-sequencing, TCR sequencing, and histology. ICC/IDC cancer cells express genes associated with metastasis and targets with potential for therapeutic intervention. Pathway analyses and ligand/receptor status model cellular interactions among ICC/IDC and the tumor microenvironment (TME) including JAG1/NOTCH. The ICC/IDC TME is hallmarked by increased angiogenesis and immunosuppressive fibroblasts (CTHRC1⁺ASPN⁺FAP⁺ENG⁺) along with fewer T cells, elevated T cell dysfunction, and increased C1QB⁺TREM2⁺APOE⁺-M2 macrophages. These findings support that cancer cell intrinsic pathways and a complex immunosuppressive TME contribute to the aggressive phenotype of ICC/IDC. These data highlight potential therapeutic opportunities to restore immune signaling in patients with ICC/IDC that may afford better outcomes.

A Preclinical Study of an 125I-Labeled PSMA Ligand for Prostate-Cancer Puncture

Purpose: Prostate cancer (PCa) is characterized by high expression of prostate-specific 1membrane antigen (PSMA), a type II transmembrane protein. Prostate-specific membrane antigen positron emission tomography (PSMA PET) has high sensitivity and specificity and can therefore be potentially used to detect PCa. Exploiting the advantages of PSMA PET imaging, in this study, we aim to develop a novel radiopharmaceutical to facilitate biopsy punching of PCa. Methods: We synthesized a high-affinity radiopharmaceutical of PSMA (¹²⁵I-PSMA-7). We evaluated the properties of ¹²⁵I-PSMA-7, including the purity, stability, affinity, partition coefficient, and toxicity. (PSMA+) 22Rv1 and (PSMA−) PC3 cell lines were used to evaluate ¹²⁵I-PSMA-7 in vitro. BALB/c nude mice bearing 22Rv1 and PC3 xenografts were used for biodistribution and imaging. The uptake of the main organs was evaluated in vivo using single photon emission computed tomography (SPECT). Results: ¹²⁵I-PSMA-7 had a purity of 99.6% and remained stable for seven days and was therefore always safe to use. ¹²⁵I-PSMA-7 had a Ki of 4.037 × 10⁻¹¹ and a partition coefficient of −1.80. The results of in vitro cellular experiments showed a high uptake by 22Rv1 cells (ranging from 2.88 ± 0.14 IA%/10⁶ at 5 min to 61.98 ± 3.43 IA%/10⁶ at 24 h, where the internalization was 46.1% at 1 h and 88.06% at 24 h). However, the uptake of PC3 cells was very low (ranging from 0.34 ± 0.08 IA%/10⁶ at 5 min to 1.60 ± 0.15 IA%/10⁶ at 24 h). The tumors’ uptake of ¹²⁵I-PSMA-7 ranged from 9.02 ± 0.30 ID%/g at 1 h to 4.11 ± 1.04 ID%/g at 7 d and the tumor/muscle ratios and tumor/blood ratios increased over time. In addition, we used γ-counter to measure cpm per milligram of tumor and muscle on days 4 and 7. The background on day 4 is 42 cpm and the tumor is 1739 cpm/mg and the muscle is 45 cpm/mg, and the background on day 7 is 74 cpm and the tumor is 1404cpm/mg and the muscle is 32 cpm/mg. At 1 h post-injection, the high uptake of ¹²⁵I-PSMA-7 resulted in clear delineation of 22Rv1-derived tumors upon imaging. By comparison, 22Rv1-blocking mice took up less ¹²⁵I-PSMA-7. Conclusions: These results show that ¹²⁵I-PSMA-7 is a promising radiotracer that could be used to puncture the prostate. ¹²⁵I-PSMA-7 could be applied to targeted biopsy, reducing the need for saturated biopsy.

Prostate specific membrane antigen positron emission tomography in primary prostate cancer diagnosis: First-line imaging is afoot

Prostate specific membrane antigen positron emission tomography (PSMA PET) is an excellent molecular imaging technique for prostate cancer. Currently, PSMA PET for patients with primary prostate cancer is supplementary to conventional imaging techniques, according to guidelines. This supplementary function of PSMA PET is due to a lack of systematic review of its strengths, limitations, and potential development direction. Thus, we review PSMA ligands, detection, T, N, and M staging, treatment management, and false results of PSMA PET in clinical studies. We also discuss the strengths and challenges of PSMA PET. PSMA PET can greatly increase the detection rate of prostate cancer and accuracy of T/N/M staging, which facilitates more appropriate treatment for primary prostate cancer. Lastly, we propose that PSMA PET could become the first-line imaging modality for primary prostate cancer, and we describe its potential expanded application.

Novel germline mutations for active surveillance and imaging strategies in prostate cancer

PURPOSE OF REVIEW

This review highlights the emerging role of genetics-lead medicine (GLM) in prostate cancer. We describe the benefits of GLM integration into prostate cancer screening, diagnosis and management. Imaging techniques enhancing prostate cancer detection are advancing concurrently, facilitating strategic active surveillance protocols for appropriately selected patients. We aim to improve clinician awareness of the role of GLM in current and future practice.

RECENT FINDINGS

We explore recent literature advancing the role of GLM in prostate cancer detection and management, particularly as this coexists with the development of imaging technology. Our current understanding of germline mutations implicated in familial prostate cancer development is summarized. We describe how these developments are being utilized to inform screening, surveillance and the development of novel therapies. We summarize current guidelines and explore factors inhibiting optimal implementation of recommendations in clinical practice.

SUMMARY

Integration and further development of genetics-lead medicine in the detection, surveillance and management of prostate cancer will improve clinical outcomes for men at risk of aggressive disease as a result of familial predispositions to prostate cancer. This review summarizes the pertinent developments in the field including improving clinician awareness to facilitate implantation of these strategies into current clinical practice.

Morphologic spectrum of treatment-related changes in prostate tissue and prostate cancer: An Updated Review

A wide range of treatment options is available to patients with prostate cancer. Some treatments are standard (currently used) while some are emerging therapies. Androgen deprivation therapy is typically reserved for localized or metastatic prostate cancer not amenable to surgery. Radiation therapy may be offered to individuals for local therapy with curative intent in low- or intermediate-risk disease that may have a high probability of progression on active surveillance or where surgery is not suitable. Focal therapy/ablation treatment is an alternative approach for those who prefer to avoid radical prostatectomy for localized disease of low- or intermediate-risk or as salvage therapy following failed radiation therapy. Chemotherapy and immunotherapy remain under investigation and are currently used for androgen-independent disease or hormone-refractory prostate cancer; however a better understand therapeutic efficacy is needed. Histopathologic changes observed in benign and malignant prostate tissue induced by hormonal therapies and radiation therapy is well described, while treatment-related effects secondary to novel therapies continue to be documented although their clinical significance is not absolutely clear. An informed and accurate evaluation of post-treatment prostate specimens requires pathologists with diagnostic acumen and knowledge relating to the histopathologic spectrum associated with each treatment option. In situations when clinical history is lacking, but morphologic features are suggestive of prior treatment, pathologists are encouraged to consult clinical colleagues regarding prior treatment history including details of when treatment was initiated and duration of therapy. This review aims to provide a concise update of current and emerging therapies for prostate cancer, histologic alterations and recommendations on Gleason grading.

177Lu-PSMA-I&T Radioligand Therapy for Treating Metastatic Castration-Resistant Prostate Cancer: A Single-Centre Study in East Asians

Purpose

There is increasing evidence for convincing efficacy and safety of ¹⁷⁷Lu-labled prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (PRLT) for metastatic castration-resistant prostate cancer (mCRPC). However, data are not available regarding the feasibility of ¹⁷⁷Lu-labled PSMA-targeted RLT in East Asians. The present study summarized the first experience with ¹⁷⁷Lu-PSMA-I&T therapy for mCRPC in China.

Methods

Forty consecutive patients with mCRPC were enrolled from December 2019 to September 2021. Eligible patients received ¹⁷⁷Lu-PSMA-I&T RLT at intervals of 8-12 weeks. Toxicity was assessed based on standardized physicians’ reports and the Common Toxicity Criteria for Adverse Events criteria. Response to PRLT was evaluated according to the changes of prostate specific antigen (PSA) response and imaging response. Quality of life (QOL), Karnofsky performance status (KPS) and pain (visual analogue scale, VAS) were also evaluated. The impacts of baseline parameters on the therapeutic effects were explored by univariate and multivariate logistic regression analyses.

Results

All patients underwent a total of 86 cycles of ¹⁷⁷Lu-PSMA-I&T (range: 1-5 cycles) with dosages of 3.70-14.43GBq per cycle, with a median of 8 months followed up. Six patients (15%) developed mild reversible xerostomia during follow-up, and 28 patients (70%) experienced grade 1-4 bone marrow dysfunction. Changes in PSA were assessed after therapy, accompanied by the partial response (PR) in 25 patients (62.5%), the stable disease (SD) in 5 patients (12.5%), and the progressive disease (PD) in 10 patients (25%), respectively. QOL, KPS (%) and VAS scores were improved significantly due to treatment (P<0.05). Overweight and elevated AST, ALP, and LDH were associated with poor outcomes.

Conclusions

¹⁷⁷Lu-PSMA-I&T achieves the favourable response and well tolerance in mCRPC, which associates with not only PSA decline but also with tumor remission including lymphadenopathy and bone metastasis. We also find that patients with overweight and high AST, ALP, and LDH should be cautious to undergo the PRLT. Large-cohort studies are warranted to confirm the initial findings and elucidate the survival benefit of the treatment.

Deep Learning in Prostate Cancer Diagnosis Using Multiparametric Magnetic Resonance Imaging With Whole-Mount Histopathology Referenced Delineations

Background: Multiparametric magnetic resonance imaging (mpMRI) plays an important role in the diagnosis of prostate cancer (PCa) in the current clinical setting. However, the performance of mpMRI usually varies based on the experience of the radiologists at different levels; thus, the demand for MRI interpretation warrants further analysis. In this study, we developed a deep learning (DL) model to improve PCa diagnostic ability using mpMRI and whole-mount histopathology data. Methods: A total of 739 patients, including 466 with PCa and 273 without PCa, were enrolled from January 2017 to December 2019. The mpMRI (T2 weighted imaging, diffusion weighted imaging, and apparent diffusion coefficient sequences) data were randomly divided into training (n = 659) and validation datasets (n = 80). According to the whole-mount histopathology, a DL model, including independent segmentation and classification networks, was developed to extract the gland and PCa area for PCa diagnosis. The area under the curve (AUC) were used to evaluate the performance of the prostate classification networks. The proposed DL model was subsequently used in clinical practice (independent test dataset; n = 200), and the PCa detective/diagnostic performance between the DL model and different level radiologists was evaluated based on the sensitivity, specificity, precision, and accuracy. Results: The AUC of the prostate classification network was 0.871 in the validation dataset, and it reached 0.797 using the DL model in the test dataset. Furthermore, the sensitivity, specificity, precision, and accuracy of the DL model for diagnosing PCa in the test dataset were 0.710, 0.690, 0.696, and 0.700, respectively. For the junior radiologist without and with DL model assistance, these values were 0.590, 0.700, 0.663, and 0.645 versus 0.790, 0.720, 0.738, and 0.755, respectively. For the senior radiologist, the values were 0.690, 0.770, 0.750, and 0.730 vs. 0.810, 0.840, 0.835, and 0.825, respectively. The diagnosis made with DL model assistance for radiologists were significantly higher than those without assistance (P < 0.05). Conclusion: The diagnostic performance of DL model is higher than that of junior radiologists and can improve PCa diagnostic accuracy in both junior and senior radiologists.

Comparison of 68Ga-labeled Prostate-specific Membrane Antigen Ligand Positron Emission Tomography/Magnetic Resonance Imaging and Positron Emission Tomography/Computed Tomography for Primary Staging of Prostate Cancer: A Systematic Review and Meta-analysis

Context

In December 2020, the US Food and Drug Administration approved a ⁶⁸Ga-labeled prostate-specific membrane antigen ligand (⁶⁸Ga-PSMA-11) for positron emission tomography (PET) in patients with suspected prostate cancer (PCa) metastasis who are candidates for initial definitive therapy. ⁶⁸Ga-PSMA PET is increasingly performed for these patients and is usually combined with computed tomography (CT). In recent years, ⁶⁸Ga-PSMA PET has been combined with high-resolution magnetic resonance imaging (MRI), which is beneficial for T staging and may further enhance the staging of primary PCa.

Objective

To compare the diagnostic accuracy of ⁶⁸Ga-PSMA PET/MRI with ⁶⁸Ga-PSMA PET/CT for staging of primary PCa.

Evidence acquisition

A comprehensive literature search was performed using Embase, PubMed/Medline, Web of Science, Cochrane Library, and Google Scholar up to June 24, 2021 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias was assessed using the QUADAS-2 tool.

Evidence synthesis

The search identified 2632 articles, of which 27 were included. The diagnostic accuracy of ⁶⁸Ga-PSMA PET/MRI, measured as the pooled natural logarithm of diagnostic odds ratio (lnDOR), was 2.27 (95% confidence interval [CI] 1.21–3.32) for detection of extracapsular extension (ECE), 3.50 (95% CI 2.14–4.86) for seminal vesicle invasion (SVI), and 4.73 (95% CI 2.93–6.52) for lymph node metastasis (LNM). For ⁶⁸Ga-PSMA PET/CT, the analysis showed lnDOR of 2.45 (95% CI 0.75–4.14), 2.94 (95% CI 2.26–3.63), and 2.42 (95% CI 2.07–2.78) for detection of ECE, SVI, and LNM, respectively. The overall risk of bias and applicability concerns were assessed as moderate and low, respectively.

Conclusions

⁶⁸Ga-PSMA PET/MRI shows high diagnostic accuracy equivalent to that of ⁶⁸Ga-PSMA PET/CT for detection of ECE, SVI, and LNM in staging of PCa. There is an urgent need for direct comparison of the two diagnostic tests in future research.

Patient summary

The use of radioactively labeled molecules that bind to prostate-specific membrane antigen (⁶⁸Ga-PSMA) for positron emission tomography (PET) scans combined with either computed tomography (CT) or magnetic resonance imaging (MRI) is increasing for prostate cancer diagnosis. There is a need for direct comparison of the two tests to demonstrate the benefit of ⁶⁸Ga-PSMA PET/MRI for determining tumor stage in prostate cancer.

Take  Home Message

After the recent US Food and Drug Administration approval of ⁶⁸Ga-labeled prostate-specific membrane antigen ligand (⁶⁸Ga-PSMA) positron emission tomography (PET) for staging of primary prostate cancer (PCa), it is expected that the use of this imaging modality will increase rapidly. Our review of the literature shows that ⁶⁸Ga-PSMA PET/magnetic resonance imaging has high diagnostic accuracy equivalent to that of ⁶⁸Ga-PSMA PET/computed tomography in primary PCa staging. There is an urgent need for direct head-to-head comparison of the two diagnostic tests in future research.

Incorporating PSMA-Targeting Theranostics Into Personalized Prostate Cancer Treatment: a Multidisciplinary Perspective

Recent developments in prostate-specific membrane antigen (PSMA) targeted diagnostic imaging and therapeutics (theranostics) promise to advance the management of primary, biochemically recurrent, and metastatic prostate cancer. In order to maximize the clinical impact of PSMA-targeted theranostics, a coordinated approach between the clinical stakeholders involved in prostate cancer management is required. Here, we present a vision for multidisciplinary use of PSMA theranostics from the viewpoints of nuclear radiology, medical oncology, urology, and radiation oncology. We review the currently available and forthcoming PSMA-based imaging and therapeutics and examine current and potential impacts on prostate cancer management from early localized disease to advanced treatment-refractory disease. Finally, we highlight the clinical and research opportunities related to PSMA-targeted theranostics and describe the importance of multidisciplinary collaboration in this space.

Establishment and prospective validation of an SUVmax cutoff value to discriminate clinically significant prostate cancer from benign prostate diseases in patients with suspected prostate cancer by 68Ga-PSMA PET/CT: a real-world study

Background and Aims: The aims of this study were to establish a maximum standardized uptake value (SUV_max) cutoff to discriminate clinically significant prostate cancer (csPCa) from benign prostate disease (BPD) by ⁶⁸Ga-labeled prostate-specific membrane antigen (⁶⁸Ga-PSMA-11) positron emission tomography/computed tomography (PET/CT) in patients with suspected prostate cancer (PCa), and to perform a prospective real-world validation of this cutoff value.

Methods: The study included a training cohort to identify an SUV_max cutoff value and a prospective real-world cohort to validate it. A retrospective analysis assessed 135 patients with suspected PCa in a large tertiary care hospital in China who underwent ⁶⁸Ga-PSMA-11 PET/CT. All patients were suspected of having PCa based on symptoms, digital rectal examination (DRE), total prostate-specific antigen (tPSA) level, and multiparameter magnetic resonance imaging (mpMRI). The ⁶⁸Ga-PSMA PET/CT results were evaluated using histopathological results from transrectal ultrasound-guided 12-core biopsy with necessary targeted biopsy as references. Patients with Gleason scores (GS) ≥7 from the biopsy results were diagnosed with csPCa, and patients with negative biopsy and follow-up results were diagnosed with BPD. Receiver operating characteristic (ROC) curve analysis was used to identify the optimal SUV_max cutoff value. The cutoff value was prospectively validated in 58 patients with suspected PCa. The diagnostic benefits of the cutoff value for clinical decision making were also evaluated.

Results: According to ROC curve analysis, the most appropriate SUV_max cutoff value for discriminating csPCa from BPD was 5.30 (sensitivity, 85.85%; specificity, 86.21%; area under the curve [AUC], 0.893). The cutoff achieved a sensitivity of 83.33%, a specificity of 81.25%, a positive predictive value (PPV) of 92.11%, a negative predictive value (NPV) of 65.00%, and an accuracy of 82.76% in the prospective validation cohort. Metastases were used as an indicator to reduce false negative results in patients with SUV_max ≤ 5.30. In patients without metastases, an SUV_max value of 5.30 was also the best cutoff to diagnose localized csPCa (sensitivity, 80.43%; specificity, 86.21%; AUC, 0.852). The cutoff discriminated localized csPCa from BPD with a sensitivity of 76.19%, a specificity of 81.25%, a PPV of 84.21%, an NPV of 72.22%, and an accuracy of 78.38% in the prospective validation cohort. The cutoff, combined with metastases, achieved an accuracy of 89.12% in all patients, increasing accuracy by 8.29% and reducing equivocal results compared with manual reading. There was a strong correlation between SUV_max and PSMA expression (r_s = 0.831, P < 0.001) and a moderate correlation between SUV_max and GS (r_s = 0.509, P < 0.001). The PSMA expression and SUV_max values of patients with csPCa were significantly higher than those of patients with BPD (P < 0.001).

Conclusion: We established and prospectively validated the best SUV_max cutoff value (5.30) for discriminating csPCa from BPD with high accuracy in patients with suspected PCa. 5.30 is an effective cutoff to discriminate csPCa patients with or without metastases. The cutoff may provide a potential tool for the precise identification of csPCa by ⁶⁸Ga-PSMA PET/CT, ensuring high accuracy and reducing equivocal results.

Cribriform Prostate Cancer: Clinical Pathologic and Molecular Considerations

Intraductal cribriform (IDC) and invasive cribriform morphologies are associated with worse prostate cancer outcomes. Limited retrospective studies have associated IDC and cribriform morphology with germline mutations in DNA repair genes, particularly BRCA2. These findings, which prompted the National Comprehensive Cancer Network (NCCN) Guidelines for Prostate Cancer and Genetic/Familial High- Risk Assessment to consider germline testing for individuals with IDC/cribriform histology, have been questioned in a recent prospective study. A deepened understanding of the molecular mechanisms driving disease aggressiveness in cribriform morphology is critical to provide more clarity in clinical decision making. This review summarizes the current understanding of IDC and cribriform prostate cancer, with an emphasis on clinical outcomes and molecular alterations.

The visibility of prostate cancer concerning underlying histopathological variances: A single-center multiparametric magnetic resonance imaging study

PURPOSE

To investigate whether prostate cancer (PCa) lesions regarding histopathological composition exhibit different morphological features on multiparametric prostate MRI (mpMRI).

METHODS

We investigated men with PCa with available mpMRI and whole-mount specimens between June 2015 to December 2020.The acquisition protocol consistent with the Prostate Imaging Reporting and Data System (PI-RADS). Two observers evaluated the images following the PI-RADS v2.1. guideline before biopsy and radical prostatectomy. The discrepancies were resolved in a joint meeting. A genitourinary pathologist reviewed the whole-digitalized mount specimens, and the lesions with Gleason score of 7 and above (3 + 4 and above), and/or cancers with a maximum diameter of 6 mm and more, and/or extraprostatic extension were accepted as clinically significant PCa. The PI-RADS scores and the diameter of the clinically significant PCa on mpMRI concerning histopathological components (i.e., cribriform component, intraductal pattern, or without cribriform component or intraductal pattern) were investigated. The clinically significant PCa foci with PI-RADS score <3 was accepted as an invisible lesion on mpMRI.

RESULTS

In all, 58 men with a total of 112 clinically significant PCa foci, were enrolled in the study. The intraductal pattern, cribriform pattern, or none of these patterns were observed in 28/112 (25 %), 43/112 (38.05 %), and 41/112 (36.60 %) tumor foci. Six out of 28 (21.42 %), 17/43 (39.53 %), and 18/41 (42.8 %) foci with an intraductal pattern, cribriform component, or without any of them, respectively, were invisible on mpMRI (P = 0.111).

CONCLUSION

Though it was not reached a statistical significance, clinically significant PCa with the cribriform component and without any intraductal or cribriform component are more likely to manifests mpMRI invisible foci than the intraductal pattern. Further multi-center studies are warranted to precisely elucidate mpMRI features of PCa regarding histopathological composition.

Prostate-Specific Membrane Antigen PET for Assessment of Primary and Recurrent Prostate Cancer with Histopathology as Reference Standard: A Systematic Review and Meta-Analysis

Prostate-specific membrane antigen PET is a promising diagnostic tool in prostate cancer. The gold standard for the detection of prostate tumor and lymph node metastases is histopathology. The aim of the present review was to investigate accuracy measures of ⁶⁸Ga/¹⁸F-labeled prostate-specific membrane antigen PET tracers in primary and recurrent prostate cancer with systematic sector-based histopathology as the reference standard. A systematic literature search was performed and 34 studies were included. Overall, prostate-specific membrane antigen PET showed high specificity, but variable sensitivity to localize known prostate cancer and detect pelvic lymph node metastases.

68Ga-PSMA PET/CT targeted biopsy for the diagnosis of clinically significant prostate cancer compared with transrectal ultrasound guided biopsy: a prospective randomized single-centre study

PURPOSE

68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) is valuable for detecting primary and recurrent prostatic lesions. This study aimed to evaluate the efficacy of 68Ga-PSMA-11 PET/CT as a triage tool for prostate biopsy (PSMA-TB) and compare with transrectal ultrasound-guided biopsy (TRUS-GB) for the diagnosis of clinically significant prostate cancer (csPCa).

METHODS

This single-centre study randomly allocated 120 patients with elevated serum prostate-specific antigen (PSA) levels (> 4 ng/ml) to PSMA-PET or TRUS group. Patients with PSMA-avid lesions (SUVmax ≥ 8.0) underwent PSMA-TB via a single-puncture percutaneous transgluteal approach (n = 25), whilst patients with negative PSMA-PET underwent systematic TRUS-GB (n = 35). All patients in the TRUS group underwent TRUS-GB directly (n = 60).

RESULTS

PCa and csPCa were detected in 26/60 (43.3%) and 24/60 (40.0%) patients in the PSMA-PET group and 19/60 (31.6%) and 15/60 (25.0%) in the TRUS group, respectively. In the PSMA-PET group, the detection rate of PCa and csPCa were significantly higher in PSMA-PET-positive than negative patients (PCa, 23/25 (92.0%) vs 3/35 (8.6%), P < 0.01; csPCa, 22/25 (88.0%) vs 2/35 (5.7%), P < 0.01). PSMA-TB detected significantly more PCa and csPCa than TRUS-GB in the TRUS controls (PCa, 21/25 (84.0%) vs 19/60 (31.6%), P < 0.01; csPCa, 20/25 (80.0%) vs 15/60 (25.0%), P < 0.01). PSMA-PET detected significantly more cases of csPCa amongst patients with PSA 4.0-20.0 ng/ml than TRUS (27.02% vs 8.82%, P < 0.05). No haematuria, urinary retention or pelvic infection was observed after PSMA-TB compare with TRUS-GB.

CONCLUSIONS

68Ga-PSMA-11 PET/CT is a feasible imaging technique that may serve as a triage tool for prostate biopsy, and may improve the detection rate of csPCa compared with TRUS-GB, especially in patients with serum PSA 4.0-20.0 ng/ml.

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) for local staging of prostate cancer: a systematic review and meta-analysis

Purpose

Prostate-specific membrane antigen positron emission tomography (PSMA-PET) has shown promise for detecting nodal and distant prostate cancer (PCa) metastases. However, its performance for local tumor staging is not as well established. The purpose of this study was to review the diagnostic performance of PSMA-PET for determining seminal vesical invasion (SVI) and extraprostatic extension (EPE).

Methods

Pubmed and Embase databases were searched until January 12, 2020. Studies assessing accuracy of PSMA-PET in determining SVI and EPE were included. Study quality was evaluated with the revised Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled sensitivity and specificity were calculated using hierarchical summary receiver operating characteristics modeling. Heterogeneity was explored using meta-regression analyses for anatomical imaging component (MRI vs CT) and by testing for a threshold effect.

Results

Twelve studies (615 patients) were included. Pooled sensitivity and specificity were 0.68 (95% CI 0.53-0.81) and 0.94 (95% CI 0.90-0.96) for SVI and 0.72 (95% CI 0.56-0.84) and 0.87 (95% CI 0.72-0.94) for EPE. Meta-regression analyses showed that for SVI, PET/MRI demonstrated greater sensitivity than PET/CT (0.87 [95% CI 0.75-0.98] vs 0.60 [95% CI 0.47-0.74]; p = 0.02 for joint model) while specificity was comparable (0.91 [95% CI 0.84-0.97] vs. 0.96 [95% CI 0.93-0.99]) but not for EPE (p = 0.08). A threshold effect was present for studies assessing EPE (correlation coefficient = 0.563 [95% CI, −0.234-0.908] between sensitivity and false-positive rate).

Conclusion

PSMA-PET has moderate sensitivity and excellent specificity for assessing local tumor extent in patients with PCa. PET/MRI showed potential for greater sensitivity than PET/CT in assessing SVI.

68Ga-PSMA-11 PET/CT combining ADC value of MRI in the diagnosis of naive prostate cancer: Perspective of radiologist

Ga-PSMA-11 positron emission computed tomography /computed tomography (PET/CT) is more sensitive than magnetic resonance imaging (MRI) in detecting prostate cancer (PCa). We evaluated the value of Ga-PSMA-11 PET/CT with MRI in treatment-naive PCa.This retrospective study was approved by the hospital ethics committee. The MRI and Ga-PSMA-11 PET/CT imaging data of 63 cases of highly suspected PCa were enrolled in this study. The SUVmax and apparent diffusion coefficient (ADC), and their ratio, were assessed as diagnostic markers to distinguish PCa from benign disease.There were 107 prostate lesions detected in 63 cases. Forty cases with 64 malignant primary lesions were confirmed PCa, whereas 23 cases had 43 benign lesions. PSMA-avid lesions correlated with hypointense signal on ADC maps and hyperintense signal on diffusion-weighted imaging. The ADC of PCa was lower than that of benign lesions, and SUVmax and SUVmax/ADC of PCa was higher than that of benign lesions (P < .01). ADC had significant negative correlation with Gleason score (GS) and SUVmax, SUVmax, and SUVmax/ADC positively correlated with GS. From ROC analysis, we established cutoff values of ADC, SUVmax, and SUVmax/ADC at 1.02 × 10mm/s, 11.72, and 12.35, respectively, to differentiate PCa from benign lesions. The sensitivity, specificity, and AUC were 90.6%, 58.1%, and 0.816 for ADC, 67.2%, 97.7%, and 0.905 for SUVmax, and 81.2%, 88.4%, and 0.929 for SUVmax/ADC, respectively.Ga-PSMA-11 PET/CT combined with MRI offers higher diagnostic efficacy in the detection of PCa than either modality alone.

Diagnostic performance of a nomogram incorporating cribriform morphology for the prediction of adverse pathology in prostate cancer at radical prostatectomy

The aim of the present study was to develop a novel nomogram that incorporated clinical factors, imaging parameters and biopsy pathological factors (including cribriform morphology) to predict adverse pathology in prostate cancer (PCa). A total of 223 patients with PCa, who had undergone preoperative multi-parametric magnetic resonance imaging and had a biopsy of Gleason pattern (GP) 4, absence of GP 5 and pure Grade Group (GG) 3 [Gleason score (GS) 3+4, GS 4+3, GS 4+4], were retrospectively enrolled onto the study. The contribution of GG to the biopsy and Prostate Imaging Reporting and Data System (PI-RADS) score for PCa harboring adverse pathology were analyzed. Univariate and multivariate logistic regression analyses were performed to determine significant pathology predictors of adverse pathology for nomogram development. The nomogram was internally validated using bootstrapping with 1,000 iterations. The diagnostic performance of the nomogram was analyzed by receiver operating characteristics (ROC) analysis and decision curve analysis (DCA). A higher biopsy GG and PI-RADS score were associated with an increased likelihood of adverse pathology. Prostate specific antigen density (PSAD), biopsy GG, cribriform morphology on biopsy and PI-RADS score were significant predictors and were included in the nomogram. The ROC area under the curve of the nomogram was 0.88 (95% confidence interval, 0.84-0.91), with a high specificity (0.91) and moderate sensitivity (0.72). The novel nomogram was shown to have a higher net benefit for the prediction of adverse pathology in PCa, compared with any individual factors determined by DCA. Overall, a novel nomogram incorporating PSAD, PI-RADS score, biopsy GG and cribriform morphology on biopsy was shown to perform well in the prediction of PCa harboring adverse pathology at the time of radical prostatectomy.

Prospective Evaluation of 68Ga-labeled Prostate-specific Membrane Antigen Ligand Positron Emission Tomography/Computed Tomography in Primary Prostate Cancer Diagnosis

BACKGROUND

Positron emission tomography (PET)/computed tomography (CT) with ⁶⁸Ga-labeled prostate-specific membrane antigen ligand (⁶⁸Ga-PSMA) may represent the most promising alternative to multiparametric magnetic resonance imaging (mpMRI) for prostate cancer (PCa) diagnosis.

OBJECTIVE

To test the diagnostic performance of ⁶⁸Ga-PSMA PET/CT in this clinical context.

DESIGN, SETTING, AND PARTICIPANTS

From January 2017 to December 2018 we prospectively enrolled 97 patients with persistently elevated prostate-specific antigen and/or Prostate Health Index score, negative digital rectal examination, and previous negative biopsy. We also included patients with either negative mpMRI or contraindications to or positive mpMRI but previous negative biopsy.

INTERVENTION

Patients underwent 68Ga-PSMA PET/CT with additional pelvic reconstruction.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint of the study was the diagnostic performance of ⁶⁸Ga-PSMA PET/CT in detecting malignant lesions and clinically significant PCa (Gleason score [GS] ≥7).

RESULTS AND LIMITATIONS

⁶⁸Ga-PSMA PET/transrectal ultrasound fusion biopsy was performed in 64 of 97 patients (66%) for 114 regions of interest (ROIs). Forty patients (41%) had already undergone mpMRI with either a negative result for PCa (n = 15; 22 ROIs) or a positive mpMRI result but a previous negative biopsy. According to pathology, 23 patients (36%) had evidence of PCa: eight (16 ROIs) with GS 6, 13 (21 ROIs) with GS 7 (3 + 4 or 4 + 3), one (2 ROIs) with GS 8, and one (2 ROIs) with GS 10. Clinically significant PCa was identified in four patients with previous negative mpMRI (25%). PET/CT demonstrated PCa in seven patients (14 ROIs) with previous positive mpMRI and negative biopsy. The median maximum standardized uptake value (SUVmax) and median SUV ratio were significantly higher for PCa lesions than for benign lesions (p <  0.001). Optimal cutoff points obtained for SUVmax (>5.4) and SUV ratio (>2.2) could identify clinically significant PCa with accuracy of 81% and 90%, respectively.

CONCLUSIONS

In our cohort of patients with high suspicion of cancer,⁶⁸Ga-PSMA PET/CT was capable of detecting malignancy and accurately identifying clinically relevant PCa.

PATIENT SUMMARY

Positron emission tomography/computed tomography with a ⁶⁸Ga-labeled ligand for prostate-specific membrane antigen is capable of detecting prostate cancer in patients with a high suspicion of cancer and a previous negative biopsy.

Diagnostic Value of 68Ga-PSMA PET/CT for Detection of Phosphatase and Tensin Homolog Expression in Prostate Cancer: A Pilot Study

Our purpose was to explore the value of ⁶⁸Ga-prostate-specific membrane antigen (PSMA) PET/CT for detection of phosphatase and tensin homolog (PTEN)-loss prostate cancer. Methods: We retrospectively enrolled 75 patients who underwent multiparametric MRI and ⁶⁸Ga-PSMA PET/CT before radical prostatectomy. Lesions were outlined on pathologic images, and regions of interest were drawn on matched multiparametric MRI and PET/CT images. Imaging parameters, including average apparent diffusion coefficient and SUV_max, were derived. Immunohistochemical staining was performed to evaluate the PTEN status. The diagnostic performance of imaging parameters was analyzed by receiver-operating-characteristic analysis. Univariate logistic regression analyses were used to evaluate the association between clinical and imaging variables and PTEN status. Results: In total, 103 lesions from 75 patients were analyzed. Of these lesions, 38 of 103 (36.9%) showed PTEN-loss status. Our study showed a strong association between SUV_max and PTEN-loss tumors both in the per-patient analysis (P < 0.01) and in the per-lesion analysis (P < 0.01), yielding sensitivity and specificity of 0.80 and 0.77, respectively, in the per-patient analysis and 0.83 and 0.74, respectively, in the per-lesion analysis. Meanwhile, higher pathologic PSMA expression was found in the PTEN-deficiency tumors. However, there was no significant difference between PTEN-loss tumors and PTEN-intact tumors using parameters such as average apparent diffusion coefficient (P > 0.05) and score on the Prostate Imaging Reporting and Data System, version 2 (P > 0.05). Surprisingly, SUV_max was a significant predictor for detection of PTEN-loss tumors (odds ratio of 7.56 and 95% confidence interval of 2.18-26.24 on per-patient analysis; odds ratio of 13.66 and 95% confidence interval of 4.32-43.24 on per-lesion analysis). Conclusion: ⁶⁸Ga-PSMA PET/CT could effectively detect aggressive PTEN-loss tumors.