The Role of Prostate-specific Membrane Antigen Positron Emission Tomography/Magnetic Resonance Imaging in Primary and Recurrent Prostate Cancer: A Systematic Review of the Literature

Surveillance After Focal Therapy for Prostate Cancer: A Comprehensive Review

Focal Therapy (FT) is an emerging treatment modality for prostate cancer (PCa). Due to its novelty, the research exploring how patients should be followed-up after treatment is limited. There is currently no established role for non-prostate-specific-antigen (PSA) biomarkers and PSMA PET. However, a combination of PSA testing, multiparametric magnetic resonance imaging (mpMRI), and systematic and targeted biopsies should routinely be used for surveillance after FT. PSA values that rise 1.0 ng/mL over the nadir after twelve months or rise 1.5 ng/mL over nadir after twenty-four to thirty-six months should raise suspicion for recurrence. The standard imaging technique is mpMRI, but it can often be difficult to interpret after FT, so using a scoring system such as prostate imaging after focal ablation (PI-FAB) or the transatlantic recommendations for prostate gland evaluation with magnetic resonance imaging after focal therapy (TARGET) allows for greater consistency between readers. This review seeks to summarize the current literature regarding surveillance after FT as it relates to biomarkers, imaging, biopsies, and consensus statements.

Identifying the best candidate for focal therapy: a comprehensive review

BACKGROUND

Despite the evidence supporting the use of focal therapy (FT) in patients with localized prostate cancer (PCa), considerable variability exists in the patient selection criteria across current studies. This study aims to review the most recent evidence concerning the optimal approach to patient selection for FT in PCa.

METHODS

PubMed database was systematically queried for studies reporting patient selection criteria in FT for PCa before December 31, 2023. After excluding non-relevant articles and a quality assessment, data were extracted, and results were described qualitatively.

RESULTS

There is no level I evidence regarding the best patient selection approach for FT in patients with PCa. Current international multidisciplinary consensus statements recommend multiparametric magnetic resonance imaging (mpMRI) followed by MRI-targeted and systematic biopsy for all candidates. FT may be considered in clinically localized, intermediate risk (Gleason 3 + 4 and 4 + 3), and preferably unifocal disease. Patients should have an acceptable life expectancy. Those with prostate volume >50 ml and erectile dysfunction should not be excluded from FT. Prostate-specific antigen (PSA) level of < 20 (ideally < 10) ng/mL is recommended. However, the utility of other molecular and genomic biomarkers in patient selection for FT remains unknown.

CONCLUSIONS

FT may be considered in well-selected patients with localized PCa. This review provides a comprehensive insight regarding the optimal approach for patient selection in FT.

Cognitive Targeted Prostate Biopsy Alone for Diagnosing Clinically Significant Prostate Cancer in Selected Biopsy-Naïve Patients: Results from a Retrospective Pilot Study

(1) Background: To identify a particular setting of biopsy-naïve patients in which it would be reasonable to offer only cognitive targeted prostate biopsy (PBx) with a transrectal approach. (2) Methods: We designed an observational retrospective pilot study. Patients with a prostatic specific antigen (PSA) level > 10 ng/mL, either a normal or suspicious digital rectal examination (DRE), and a lesion with a PI-RADS score ≥ 4 in the postero-medial or postero-lateral peripheral zone were included. All patients underwent a transrectal PBx, including both systematic and targeted samples. The detection rate of clinically significant prostate cancer (csPCa) (Gleason Score ≥ 7) was chosen as the primary outcome. We described the detection rate of csPCa in systematic PBx, targeted PBx, and overall PBx. (3) A total of 92 patients were included. Prostate cancer was detected in 84 patients (91.30%) with combined biopsies. A csPCa was diagnosed in all positive cases (100%) with combined biopsies. Systematic PBxs were positive in 80 patients (86.96%), while targeted PBxs were positive in 84 men (91.30%). Targeted PBx alone would have allowed the diagnosis of csPCa in all positive cases; systematic PBx alone would have missed the diagnosis of 8/84 (9.52%) csPCa cases (4 negative patients and 4 not csPCa) (p = 0.011). (4) Conclusions: Cognitive targeted PBx with a transrectal approach could be offered alone to diagnose csPCa in biopsy-naïve patients with PSA ≥ 10 ng/mL, either normal or suspicious DRE, and a lesion with PI-RADS score ≥ 4 in the postero-medial or postero-lateral peripheral zone.

Prostate Cancer in Transgender Women: Epidemiology, Clinical Characteristics, and Management Challenges

PURPOSE OF REVIEW

To systematically review the evidence on prostate cancer (PCa) in transgender women (TGW).

RECENT FINDINGS

A total of 25 studies were included. Fourteen articles were case reports or case series describing 21 TGW with PCa; 11 papers focused primarily on assessing the incidence or screening of PCa in TGW. The median (range) age of patients with PCa was 63 (45-78) years. Median (range) PSA at diagnosis was 7.5 (0.4-1710) ng/mL. Prostate biopsy detected ISUP 3-5 in 10 (67%) cases. T3-4 stages were described in 7 (64%) patients. Three (14.3%) cases of nodal involvement and 2 (9.5%) of metastases were reported at diagnosis. First-line therapy included radical prostatectomy or radiotherapy ± androgen deprivation therapy in 14 (74 %) subjects. Median (range) follow-up was 24 (2-120) months. A good response to first-line therapy was recorded in 8 (47.1%) cases. Median (range) incidence of PCa in TGW was 44.1 (4.34-140) cases per 100,000 person-years. PCa was significantly less frequent in TGW than in cisgender males (HR 0.4, 95% CI 0.2-0.9). Risk of death after PCa diagnosis was significantly higher in TGW compared to cisgender males (HR 1.91, 95% CI 1.06-3.45). TGW had lower lifetime PSA rates (48% vs. 64.6%, p = 0.048) than cisgender males. Few cases of PCa in TGW are currently reported. PCa seems significantly less frequent in TGW than in cisgender males; however, some data suggest a possible higher mortality in this cohort. TGW appear to have less access to PSA testing than cisgender men.

Clinical Efficacy and Openness to New Challenges of Low Dose Rate Brachytherapy for Prostate Cancer

Over a century ago, low-dose-rate (LDR) brachytherapy was introduced to treat prostate cancer (PCa). Since then, it has been widely applied worldwide, including in East Asia. LDR brachytherapy has been performed in 88 institutes in Japan. Beneficial clinical outcomes of LDR brachytherapy for intermediate-to-high-risk PCa have been demonstrated in large clinical trials. These clinical outcomes were achieved through advances in methods, such as urological precise needle puncture and seed placement, and the quantitative decision making regarding radiological parameters by radiation oncologists. The combined use of LDR brachytherapy with other therapeutic modalities, such as external beam radiation and androgen deprivation therapy, for the clinical risk classification of PCa has led to better anticancer treatment efficacy. In this study, we summarized basic LDR brachytherapy findings that should remain unchanged and be passed down in urology departments. We also discussed the applications of LDR brachytherapy for PCa in various clinical settings, including focal and salvage therapies. In addition, we highlighted technologies associated with brachytherapy that are under development.

A Review of Modern Imaging Landscape for Prostate Cancer: A Comprehensive Clinical Guide

The development of prostate cancer imaging is rapidly evolving, with many changes to the way patients are diagnosed, staged, and monitored for recurrence following treatment. New developments, including the potential role of imaging in screening and the combined diagnostic and therapeutic applications in the field of theranostics, are underway. In this paper, we aim to outline the current landscape in prostate cancer imaging and look to the future at the potential modalities and applications to come.

Management of Patients with Recurrent and Metachronous Oligometastatic Prostate Cancer in the Era of PSMA PET

Prostate-specific membrane antigen (PSMA) positron emission tomography (PET) scans have higher sensitivity and specificity for detecting lymph nodes or metastatic disease relative to conventional imaging in prostate cancer staging. Since its FDA approval and incorporation into treatment guidelines, the use of PSMA PET has increased in patients undergoing initial staging, those with recurrence after initial definitive treatment, and patients with metastatic disease. Although the early detection of metastatic lesions is changing disease management, it is unclear whether this impact on management translates into clinical benefit. This review will summarize evidence pertaining to the change in patient management due to PSMA PET use and will discuss the implications of PSMA PET on treatment decisions in prostate cancer, particularly in the settings of biochemical recurrence and metachronous oligometastatic disease.

Failure Patterns by PSMA PET for Recurrent Prostate Cancer after Prostatectomy and Salvage Radiation

OBJECTIVE

To characterize patterns of failure using prostate-specific membrane antigen positron emission tomography (PSMA PET) after radical prostatectomy (RP) and salvage radiotherapy (SRT).

METHODS

Patients with rising PSA post-RP+SRT underwent 68Ga-HBED-iPSMA PET/CT on a single-arm, prospective imaging trial (NCT03204123). Scans were centrally reviewed with pattern-of-failure analysis by involved site. Positive scans were classified using 3 failure categories: pelvic nodal, extra-pelvic nodal or distant non-nodal. Associations with failure categories were analyzed using cumulative incidence and generalized logits regression.

RESULTS

We included 133 men who received SRT a median of 20 months post-RP; 56% received SRT to the prostatic fossa alone, while 44% received pelvic SRT. PSMA PET/CT was performed a median of 48 months post-SRT. Overall, 31% of PSMA PET/CT scans were negative, 2% equivocal and 67% had at least 1 positive site. Scan detection was significantly associated with PSA level prior to PSMA PET/CT. Analysis of 89 positive scans demonstrated pelvic nodal (53%) was the most common relapse and fossa relapse was low (9%). Overall, positive scans were pelvic (n = 35, 26%), extra-pelvic nodal (n = 26, 20%) or distant non-nodal failure (n = 28, 21%), and 70% of positive scans were oligorecurrent. We observed similar cumulative incidence for all failure categories and relatively few clinicodemographic associations. Men treated with pelvic SRT had reduced odds of pelvic failure versus exclusive fossa treatment.

CONCLUSION

Pelvic, extra-pelvic nodal, and distant non-nodal failures occur with similar incidence post-SRT. Regional nodal relapse is relatively common, especially with fossa-only SRT. A high oligorecurrence rate suggests a potentially important role for PSMA-guided focal therapies.

Micro-Ultrasound in the Diagnosis and Staging of Prostate and Bladder Cancer: A Comprehensive Review

Background and Objectives: Multiparametric magnetic resonance imaging (mpMRI) of the prostate and prostate-specific membrane antigen positron emission tomography (PSMA PET) are some examples of how the advancement of imaging techniques have revolutionized the diagnosis, staging, and consequently management of patients with prostate cancer (PCa). Although with less striking results, novel radiological modalities have also been proposed for bladder cancer (BCa) in recent years. Micro-ultrasound (MUS) is an imaging examination characterized by high real-time spatial resolution, recently introduced in the urological field. This article aimed to describe the current evidence regarding the application of MUS for the diagnosis and staging of PCa and BCa. Materials and Methods: We designed a narrative review. A comprehensive search in the MEDLINE, Scopus, and Cochrane Library databases was performed. Articles in English-language and published until July 2022 were deemed eligible. Retrospective and prospective primary clinical studies, as well as meta-analyses, were included. Results: MUS-guided prostate biopsy showed high sensitivity (0.91, 95% CI, 0.79-0.97) in the diagnosis of clinically significant PCa (csPCa). It was associated with a higher detection rate of csPCa than a systematic biopsy (1.18, 95% CI 0.83-1.68). No significant difference was found between MUS and mpMRI-guided biopsy in the total detection of PCa (p = 0.89) and in the detection of Grade Groups ≥ 2 (p = 0.92). The use of MUS to distinguish between non-muscle-invasive and muscle-invasive BCa was described, highlighting an up-staging with MUS only in a minority of cases (28.6%). Conclusions: Promising findings have emerged regarding the feasibility and accuracy of MUS in the diagnosis and staging of PCa and BCa. However, the available evidence is limited and should be considered preliminary.

Prospective intraindividual comparison of 18F-PSMA-7Q and 18F-DCFPyL PET/CT in patients with newly diagnosed prostate cancer

OBJECTIVE

Fluorine 18 (18F)-2-(3-{1-Carboxy-5-[(6-[(18)F]fluoro-pyridine-3-carbonyl)-amino]-pentyl}-ureido)-pentanedioic acid (DCFPyL) is an early 18F-labeled prostate-specific membrane antigen (PSMA) targeted PET tracer that has shown promise in the diagnostic workup of prostate cancer and was recently approved by the US Food and Drug Administration. 18F-PSMA-7Q is a novel 18F-labeled PSMA-ligand PET tracer designed and synthesized by our team. This study compared the tracer-specific positron emission tomography/computed tomography (PET/CT) characteristics of 18F-PSMA-7Q with those of 18F-DCFPyL in patients with newly diagnosed prostate cancer.

METHODS

Ten patients received similar doses of 18F-DCFPyL and 18F-PSMA-7Q 48 h apart and were imaged 1 h after injection on the same PET/CT scanner. Normal-organ biodistribution and tumor uptake were quantified using maximum and mean standardized uptake values (SUVmax and SUVmean), and all lesions were assigned a molecular imaging PSMA (miPSMA) score based on Prostate Cancer Molecular Imaging Standardized Evaluation criteria.

RESULTS

Seventeen lesions were detected in the 10 patients by both 18F-DCFPyL and 18F-PSMA-7Q. No statistically significant difference was observed when comparing the SUVmax and SUVmean of 18F-DCFPyL and 18F-PSMA-7Q in the lesions and parotid gland. The κ value for the miPSMA scores of the lesions between the two tracers was 0.907, indicating excellent agreement.

CONCLUSION

18F-PSMA-7Q can be used in clinical research as reliably as 18F-DCFPyL. The limited urinary excretion of 18F-PSMA-7Q may represent a potential advantage over 18F-DCFPyL for detection of lesions in the pelvis, which need to be verified by further studies.

Value of Targeted Biopsies and Combined PSMA PET/CT and mp-MRI Imaging in Locally Recurrent Prostate Cancer after Primary Radiotherapy

Simple Summary

After primary radiotherapy for prostate cancer, patients may develop an isolated local recurrence. The diagnostic workup of these recurrences guides decision making for potential focal salvage treatments. The aim of this study was to determine the positive predictive value (PPV) of combined multiparametric (mp) MRI and prostate specific membrane antigen (PSMA) PET/CT imaging in this setting, with histological conformation using MR-guided targeted biopsies. In 41 patients counseled for focal salvage high dose rate (HDR) brachytherapy, a PPV of 97.6% was found for combined mp-MRI and PSMA PET/CT. Therefore, biopsies can safely be omitted in these patients.

Abstract

Radiorecurrent prostate cancer is conventionally confirmed using systematic and/or targeted biopsies. The availability of multiparametric (mp) MRI and prostate specific membrane antigen (PSMA) PET/CT has increased diagnostic accuracy. The objective was to determine the positive predictive value (PPV) of combined mp-MRI and PSMA PET/CT and whether pathology verification with MR-targeted biopsies remains necessary for patients with radiorecurrent prostate cancer. Patients with locally recurrent prostate cancer who were referred for 19 Gy single-dose MRI-guided focal salvage high dose rate (HDR) brachytherapy between 2015 and 2018 were included in the current analysis. Patients were selected if they underwent pre-biopsy mp-MRI and PSMA PET/CT. Based on these images, lesions suspect for isolated tumor recurrence were transperineally biopsied using transrectal ultrasound fused with MRI. A total of 41 patients were identified from the database who underwent cognitive targeted (n = 7) or MRI/PSMA-transrectal ultrasound (TRUS) fused targeted (n = 34) biopsies. A total of 40 (97.6%) patients had positive biopsies for recurrent cancer. Five patients initially had negative biopsies (all MRI/PSMA-TRUS fusion targeted), four of whom recurrence was confirmed after a re-biopsy. One (2.4%) patient refused re-biopsy, leading to a positive predictive value (PPV) for combined imaging of 97.6%. Biopsies can therefore safely be withheld when the results of the combined mp-MRI and PSMA PET/CT are conclusive, avoiding an unnecessary invasive and burdensome procedure.