Innovations in imaging modalities for recurrent and metastatic prostate cancer: a systematic review

Head-to-head comparison of prostate-specific membrane antigen PET and multiparametric MRI in the diagnosis of pretreatment patients with prostate cancer: a meta-analysis

OBJECTIVES

To compare prostate-specific membrane antigen (PSMA) PET with multiparametric MRI (mpMRI) in the diagnosis of pretreatment prostate cancer (PCa).

METHODS

Pubmed, Embase, Medline, Web of Science, and Cochrane Library were searched for eligible studies published before June 22, 2022. We assessed risk of bias and applicability by using QUADAS-2 tool. Data synthesis was performed with Stata 17.0 software, using the "midas" and "meqrlogit" packages.

RESULTS

We included 29 articles focusing on primary cancer detection, 18 articles about primary staging, and two articles containing them both. For PSMA PET versus mpMRI in primary PCa detection, sensitivities and specificities in the per-patient analysis were 0.90 and 0.84 (p<0.0001), and 0.66 and 0.60 (p <0.0001), and in the per-lesion analysis they were 0.79 and 0.78 (p <0.0001), and 0.84 and 0.82 (p <0.0001). For the per-patient analysis of PSMA PET versus mpMRI in primary staging, sensitivities and specificities in extracapsular extension detection were 0.59 and 0.66 (p =0.005), and 0.79 and 0.76 (p =0.0074), and in seminal vesicle infiltration (SVI) detection they were 0.51 and 0.60 (p =0.0008), and 0.93 and 0.96 (p =0.0092). For PSMA PET versus mpMRI in lymph node metastasis (LNM) detection, sensitivities and specificities in the per-patient analysis were 0.68 and 0.46 (p <0.0001), and 0.91 and 0.90 (p =0.81), and in the per-lesion analysis they were 0.67 and 0.36 (p <0.0001), and 0.99 and 0.99 (p =0.18).

CONCLUSION

PSMA PET has higher diagnostic value than mpMRI in the detection of primary PCa. Regarding the primary staging, mpMRI has potential advantages in SVI detection, while PSMA PET has relative advantages in LNM detection.

CLINICAL RELEVANCE STATEMENT

The integration of prostate-specific membrane antigen (PSMA) PET into the diagnostic pathway may be helpful for improving the accuracy of prostate cancer detection. However, further studies are needed to address the cost implications and evaluate its utility in specific patient populations or clinical scenarios. Moreover, we recommend the combination of PSMA PET and mpMRI for cancer staging.

KEY POINTS

• Prostate-specific membrane antigen PET has higher sensitivity and specificity for primary tumor detection in prostate cancer compared to multiparametric MRI. • Prostate-specific membrane antigen PET also has significantly better sensitivity and specificity for lymph node metastases of prostate cancer compared to multiparametric MRI. • Multiparametric MRI has better accuracy for extracapsular extension and seminal vesicle infiltration compared to ate-specific membrane antigen PET.

Prostate-specific membrane antigen positron emission tomography compared to multiparametric MRI for prostate cancer diagnosis: a protocol for a systematic review and meta-analysis

INTRODUCTION

The introduction of multiparametric MRI (mpMRI) has improved almost every aspect of the prostate cancer diagnostic pathway. However, the novel imaging technique, prostate-specific membrane antigen positron emission tomography (PSMA PET) may have demonstrable accuracy in detecting and staging prostate cancer. Here, we describe a protocol for a systematic review and meta-analysis comparing mpMRI to PSMA PET for the diagnosis of suspected prostate cancer.

METHODS AND ANALYSIS

A systematic search of MEDLINE, EMBASE, PubMed and Cochrane databases will be conducted. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines will be followed for screening, data extraction, statistical analysis and reporting. Included papers will be full-text articles providing original data, written in English articles and comparing the use of PSMA PET with mpMRI in the diagnosis of prostate cancer. All studies published between July 1977 and March 2021 will be eligible for inclusion. Study bias and quality will be assessed using Quadas-2 score. To ensure the quality of the reporting of studies, this protocol is written following the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols 2015 checklist.

ETHICS AND DISSEMINATION

Ethical approval will not be required for this systematic review. Findings will be disseminated through peer-reviewed publications and presentations at both national and international conferences.

PROSPERO REGISTRATION NUMBER

CRD42021239296.

Treatment of the primary in metastatic prostate cancer

PURPOSE OF REVIEW

The standard treatment in metastatic prostate cancer (mPCa) is systemic, based on androgen deprivation therapy recommended in different forms, alone or combined with abiraterone acetate or docetaxel. The aim of this review is to synthesize the available data from literature regarding the optimal treatment of the primary in patients diagnosed with metastatic prostate cancer.

RECENT FINDINGS

Multimodal treatments offer the best chance for survival for these patients, but the optimal strategy lacks consensus. Using retrospective studies as an argument, recent articles sustain the clinical and oncological benefits of local therapies in hormone-naïve metastatic prostate cancer, represented by radical prostatectomy or radiotherapy. Through these procedures, local control of disease can be achieved, thus avoiding potential complications and further surgical interventions. Even if the current results are not evenly relevant, the treatment of the primary along with metastasis-directed therapy could improve survival and even cure-selected patients.

SUMMARY

This article emphasizes important aspects regarding a feasible management of mPCa, with possible impact on subsequent guidelines. The expected results from ongoing trials may provide another perspective in treatment of these cases.

Metastasis-directed therapy and prostate-targeted therapy in oligometastatic prostate cancer: a systematic review

INTRODUCTION

The aim of this review was to summarize the available evidence on the role of metastasis-directed therapy (MDT) and/or prostate-targeted therapy (PTT) in the setting of oligometastatic prostate cancer (PCa).

EVIDENCE ACQUISITION

We searched PubMed, the Web of Science, and the Cochrane Library databases. The following keywords were used: ("prostate cancer" OR "prostate carcinoma" OR "prostate neoplasm" OR "prostate tumor") AND ("oligometastatic" OR "oligometastasis" OR "PSMA") AND ("surgery" OR "prostatectomy" OR "radical prostatectomy" OR "cytoreductive" OR "local treatment" OR "radiotherapy" OR "stereotactic" OR "stereotaxic") AND ("survival" OR "mortality").

EVIDENCE SYNTHESIS

After evaluating the selection criteria, 81 studies were evaluated for our endpoints. We included 22 studies for PTT of synchronous mPCa. There have been no randomized studies on cytoreductive prostatectomy (cRP). Four prospective studies showed that cRP was feasible but did not contribute to a positive effect on overall survival (OS). Regarding PTT-radiotherapy, two randomized controlled phase 3 trials showed that OS was improved in men with a low metastatic burden. Regarding MDT of metachronous lymph node recurrence, we included 29 retrospective studies. For MDT of oligometastases, we included 30 studies. One randomized phase 2 trial showed that androgen deprivation therapy-free survival improved with stereotactic body radiation therapy compared to that with surveillance; however, benefits on OS remain unclear.

CONCLUSIONS

We performed a comprehensive overview of the current literature on MDT and PTT. The feasibility of MDT and PTT is supported by several retrospective studies. Nevertheless, there remains a lack of high-quality trials to prove its survival benefits. Results from ongoing prospective trials data are awaited.

64CuCl2 PET/CT as a potential new imaging method in prostate cancer: illusion or reality?

Copper (Cu) is an essential element for many cellular functions, including proliferation and angiogenesis. High serum Cu levels have been demonstrated in patients with neoplasia as well as high intra-tumoral Cu levels have been reported. Preclinical and clinical evidences suggest its use, in the form of ⁶⁴Copper chloride (⁶⁴CuCl<inf>2</inf>), as metabolic PET tracer in cancer diagnosis and therapy. Specifically, the use of ⁶⁴CuCl<inf>2</inf> in human prostate cancer (PCa) evidenced a high uptake of ⁶⁴CuCl<inf>2</inf> in tumoral prostate and involved regional lymph nodes in a staging setting and high sensitivity for local recurrence and lymph nodes detection in restaging, indicating its great potential. However, further and more solid clinical evidences are needed. On the other hand, ⁶⁴CuCl<inf>2</inf> seems to be a promising radiometabolic drug with great cytotoxic abilities on PCa cells. We have collected the most recent and relevant findings on its potential uses and limitations for the study and treatment of PCa, together with its possible translation in daily clinical practice.

Simultaneous whole-body PET/MRI with integrated multiparametric MRI for primary staging of high-risk prostate cancer

PURPOSE

Whole-body positron emission tomography/magnetic resonance imaging (wbPET/MRI) is a promising diagnostic tool of recurrent prostate cancer (PC), but its role in primary staging of high-risk PC (hrPC) is not well defined. Thus, the aim was to compare the diagnostic accuracy for T-staging of PET-blinded reading (PBR) and PET/MRI.

METHODS

In this prospective study, hrPC patients scheduled to radical prostatectomy (RPx) with extended lymphadenectomy (eLND) were staged with wbPET/MRI and either ⁶⁸Ga-PSMA-11 or ¹¹C-choline including simultaneous multiparametric MRI (mpMRI). Images were assessed in two sessions, first as PBR (mpMRI and wbMRI) and second as wbPET/MRI. Prostate Imaging Reporting and Data System criteria (PIRADS v2) were used for T-staging. Results were correlated with the exact anatomical localization and extension as defined by histopathology. Diagnostic accuracy of cTNM stage according to PBR was compared to pathological pTNM stage as reference standard.

RESULTS

Thirty-four patients underwent wbPET/MRI of ⁶⁸Ga-PSMA-11 (n = 17) or ¹¹C-choline (n = 17). Twenty-four patients meeting the inclusion criteria of localized disease ± nodal disease based on imaging results underwent RPx and eLND, whereas ten patients were excluded from analysis due to metastatic disease. T-stage was best defined by mpMRI with underestimation of tumor lesion size by PET for both tracers. N-stage yielded a per patient sensitivity/specificity comparable to PBR.

CONCLUSION

MpMRI is the primary modality for T-staging in hrPC as PET underestimated T-stage in direct comparison to final pathology. In this selected study, cohort MRI shows no inferiority compared to wbPET/MRI considering N-staging.

Bone-targeted therapy in castration-resistant prostate cancer: where do we stand?

INTRODUCTION

In the last years, there have been significant developments in the therapeutic armamentarium of metastatic castration-resistant prostate cancer (mCRPC). New evidence shows that the addition of bone-targeted agents (BTA) to "life-prolonging agents" result in improved clinical benefit. This review aims to give an overview of data for the use of BTAs in a new era of mCRPC where new agents are used in daily practice.

EVIDENCE ACQUISITION

A non-systematic review of the literature was performed combining the keywords: "castration-resistant prostate cancer" and "bone-targeted therapy". The primary objective was to provide a critical assessment of data for the use of BTAs in mCRPC, and the secondary objective was to assess novel targeted therapy.

EVIDENCE SYNTHESIS

Zoledronic acid and denosumab have shown to be effective in reducing the risk of SREs in patients with mCRPC. The point at which treatment with bisphosphonates or denosumab should be initiated during PCa evolution has yet to be determined. The EMA has restricted the usage of Ra-223 to patients who have had two previous treatments for mCRPC to the bone or who cannot receive other treatments. Ra-223 should only be used as monotherapy or in combination with ADT for the treatment of mCRPC, symptomatic bone metastases and without visceral metastases. With recent developments in PSMA-targeted radiopharmaceuticals, PSMA RLT agents are now under investigation for the treatment of mCRPC.

CONCLUSIONS

Reducing skeletal-related morbidity remains a crucial goal of palliative life-extending therapy in mCRPC. New data about dosing schedules and combinations of different treatments will continue to refine the optimal strategy for incorporating BTAs into the new treatment paradigms for PCa. Novel molecules such as PSMA-targeted small molecules promise theranostic agents in the management of PCa patients.

Body Mass Index and prostatic-specific antigen are predictors of prostate cancer metastases in patients undergoing robot-assisted radical prostatectomy and extended pelvic lymph node dissection

BACKGROUND

The aim of this study was to investigate the risk factors contributing to multiple lymph node invasion (LNI) in patients with prostate cancer (PCa) undergoing extended pelvic lymph node dissection (ePLND) during robot assisted radical prostatectomy (RARP).

METHODS

A total of 211 patients who underwent RARP and ePNLD from June 2013 to March 2017 were classified according to lymph node status in the surgical specimen (absent, single or multiple). Risk factors of LNI were evaluated by the multinomial logistic regression model. A receiver operating characteristic (ROC) curve and area under the curve (AUC) were used to assess the efficacy of factors and model evaluation.

RESULTS

On multivariate analysis, the risk of multiple LNI, was independently increased by Body Mass Index (BMI) (odds ratio [OR] 1.194; P=0.026) and prostate-specific antigen (PSA) (OR=1.089; P=0.014) when compared to patients without LNI. ROC curves indicated that both BMI (AUC=0.702) and PSA (AUC=0.732) had fair discrimination power. For each unit of increase in PSA, the odds of multiple lymph node invasion increased by 8.9% and for each unit increase of BMI, the odds of multiple LNI increased by 19.4%.

CONCLUSIONS

The risk of multiple LNI was independently predicted by PSA and BMI with fair discrimination power.

Correlation between PSA kinetics and PSMA-PET in prostate cancer restaging: A meta-analysis

BACKGROUND

Serum prostate-specific antigen (PSA) may predict the risk of positive positron emission tomography/computed tomography with radiolabelled prostate-specific membrane antigen (PSMA-PET/CT) in patients with biochemical recurrent prostate cancer (BRPCa). However, to date, there are no clear data regarding the correlation between PSA kinetics and PSMA-PET findings. We performed a systematic review and meta-analysis to provide evidence-based data in this setting.

METHODS

A comprehensive literature search of studies published through October 2018 in PubMed/MEDLINE, EMBASE and Cochrane library databases was performed. A meta-analysis to establish the detection rate (DR) of PSMA-PET using different cut-off values of PSA doubling time (PSAdt) and a pooled analysis to establish whether shorter PSAdt may predict positive PSMA-PET results was performed in patients with BRPCa.

RESULTS

Twelve articles were included in the systematic review, and eight articles (including about 1400 patients) were selected for the meta-analysis. The pooled DR including 95% confidence intervals (95%CI) of PSMA-PET in restaging prostate cancer (PCa) patients was 72% (95%CI:60%-82%), increasing to 83% (95%CI:75%-90%) when PSAdt was ≤6 months and decreasing to 60% (95%CI:37%-80%) when PSAdt was >6 months, without a statistical significant difference. PSAdt ≤6 months may predict the positive result of PSMA-PET (pooled odds ratio: 3.22; 95%CI:1.17-8.88). Statistical heterogeneity among the included studies was found.

CONCLUSIONS

PSA kinetics, and in particular shorter PSAdt, may be predictor of PSMA-PET positivity in patients with BRPCa. Further larger studies in this setting are warranted.

Oligometastatic prostate cancer and salvage lymph node dissection: systematic review

INTRODUCTION

We provide a comprehensive description of the physio-pathological theories behind oligometastatic prostate cancer (PCa) and analyze modern imaging techniques, presenting a systematic review of the available evidences regarding salvage lymph node dissection (sLND).

EVIDENCE ACQUISITION

A systematic review was attempted. The PubMed/Medline database was searched for "salvage" AND ("lymph node dissection" OR "lymphadenectomy") AND "prostate" AND "cancer." Only English publications were targeted. Relevant original articles addressing the role of sLND in PCa were selected.

EVIDENCE SYNTHESIS

Biochemical response (BR) was reported in 10-79.5% of the cases overall. These results were not durable and biochemical recurrence occurred in 54.5-93.8% of the cases, within 5 years. Furthermore, 50-80% of patients received some kind of adjuvant treatment right after sLND, regardless post-operative prostate-specific antigen levels. Surgery-related morbidity was low, with a 0-27% incidence of Clavien-Dindo III complications. No sLND-related deaths were observed.

CONCLUSIONS

sLND is not associated with a durable response over time but may postpone HT and its related complications, in selected patients. Although a limited morbidity was reported, sLND remains technically demanding and a careful selection of patients is advisable.