Imaging and evaluation of patients with high-risk prostate cancer

Utility of PSMA-PET derived volumetric parameters in initial risk stratification and prediction of prostate cancer metastasis - a head-to-head comparison of the radiotracers 18F-PSMA-1007 and 68Ga-PSMA-11

OBJECTIVE

This study aimed to explore and compare the utility of baseline 18F-PSMA-1007 and 68Ga-PSMA-11 PET/computed tomography (CT) derived volumetric parameters in initial risk stratification and prediction of prostate cancer (PCa) metastasis.

METHODS

Forty treatment-naïve, biopsy-proven intermediate-/high-risk PCa patients were prospectively recruited. Each patient underwent PET/CT with 68Ga-PSMA-11 and 18F-PSMA-1007 (within 2 weeks). The maximum and mean standardized uptake values (SUVmax and SUVmean) of primary tumor, prostate PSMA-tumor volume (PSMA-TVp), and prostate total lesion PSMA (TL-PSMAp) were measured.

RESULTS

PSMA-TVp and TL-PSMAp (with both radiotracers) mostly exhibited moderate-to-strong correlation with Gleason score, serum prostate-specific antigen level and clinical tumor stage (Spearman ρ = 0.361-0.783, P-values ≤0.022). Primary tumor SUVmax values were similar across initial risk categories. PSMA-TVp and TL-PSMAp, however, were significantly higher in high-risk PCa compared to intermediate-risk PCa (P-values ≤0.001). Receiver operating characteristic (ROC) curve analysis revealed that F-PSMA-TVp, Ga-PSMA-TVp, F-TL-PSMAp, and Ga-TL-PSMAp (optimal cutoff values of 20.9, 23.4, 142.5, and 144.8, respectively) could effectively differentiate high-risk from intermediate-risk PCa [area under the ROC curve (AUCs) 0.859-0.898, P-values <0.001] with high sensitivity (~68.8-75%) and excellent specificity (100%). PSMA-TVp and TL-PSMAp (with both radiotracers) could predict presence of regional and extraregional nodal metastasis (AUCs 0.703-0.801, P-values ≤0.03) with moderate sensitivity (~47.8-70.6%) and excellent specificity (~82.6-94.1%).

CONCLUSION

Our results suggest that baseline PSMA-PET primary tumor volumetric parameters provide a noninvasive, objective, and accurate index for initial risk stratification and can predict presence of regional and extraregional nodal metastasis in PCa patients. Larger studies are warranted to evaluate their incremental role over conventional parameters.

Emerging Role of Nuclear Medicine in Prostate Cancer: Current State and Future Perspectives

Prostate cancer is the most frequent epithelial neoplasia after skin cancer in men starting from 50 years and prostate-specific antigen (PSA) dosage can be used as an early screening tool. Prostate cancer imaging includes several radiological modalities, ranging from ultrasonography, computed tomography (CT), and magnetic resonance to nuclear medicine hybrid techniques such as single-photon emission computed tomography (SPECT)/CT and positron emission tomography (PET)/CT. Innovation in radiopharmaceutical compounds has introduced specific tracers with diagnostic and therapeutic indications, opening the horizons to targeted and very effective clinical care for patients with prostate cancer. The aim of the present review is to illustrate the current knowledge and future perspectives of nuclear medicine, including stand-alone diagnostic techniques and theragnostic approaches, in the clinical management of patients with prostate cancer from initial staging to advanced disease.

ACR Appropriateness Criteria® Pretreatment Detection, Surveillance, and Staging of Prostate Cancer: 2022 Update

Prostate cancer is second leading cause of death from malignancy after lung cancer in American men. The primary goal during pretreatment evaluation of prostate cancer is disease detection, localization, establishing disease extent (both local and distant), and evaluating aggressiveness, which are the driving factors of patient outcomes such as recurrence and survival. Prostate cancer is typically diagnosed after the recognizing elevated serum prostate-specific antigen level or abnormal digital rectal examination. Tissue diagnosis is obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy, commonly with multiparametric MRI without or with intravenous contrast, which has recently been established as standard of care for detecting, localizing, and assessing local extent of prostate cancer. Although bone scintigraphy and CT are still typically used to detect bone and nodal metastases in patients with intermediate- or high-risk prostate cancer, novel advanced imaging modalities including prostatespecific membrane antigen PET/CT and whole-body MRI are being more frequently utilized for this purpose with improved detection rates. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Has the Landscape of Immunotherapy for Prostate Cancer Changed? A Systematic Review and Post Hoc Analysis

Prostate cancer (PCa) is the second leading cause of cancer-causing death in the United States. As the most common malignancy in men, it is pertinent to explore whether novel immunotherapies may improve the quality of life and overall survival (OS) of patient populations. This systematic review and post hoc analysis curates a patient-by-patient pool of evidence adhering to PRISMA Statement 2020 guidelines. In total, 24 patients were analyzed for treatment history and associated variables including prostate-specific antigen (PSA) levels at diagnosis and post-treatment, Gleason score, secondary tumor locations, success/failure of therapy, and post-immunotherapy outcomes including OS. In total, 10 types of immunotherapies were identified with Pembrolizumab (among 8 patients) followed by IMM-101 (among 6 patients) being the most commonly administered. The mean OS for all patients was 27.8 months (24 patients) with the relatively highest mean OS reported with IMM-101 (56 months) followed by tumor-infiltrating lymphocytes (30 months). This research article provides critical insights into the evolving landscape of immunotherapies being tested for PCa and addresses gaps in oncological research to advance the understanding of PCa.

18F-PSMA-1007 PET/CT-derived semi-quantitative parameters for risk stratification of newly diagnosed prostate cancer

Purpose

This study aimed to assess the value of ¹⁸F-PSMA-1007 positron emission tomography/computed tomography (PET/CT)-derived semi-quantitative parameters of primary tumor for risk stratification of newly diagnosed prostate cancer (PCa).

Methods

Sixty patients referred for ¹⁸F-PSMA-1007 PET/CT imaging for primary PCa were retrospectively analyzed and classified into the low-intermediate-risk (LIR) or high-risk (HR) group. The maximum standardized uptake value (SUVmax) of primary tumor, prostate total lesion PSMA (TL-PSMAp), and prostate PSMA-tumor volume (PSMA-TVp) were measured, and group differences were evaluated using the Mann-Whitney U test. Spearman's correlation was performed to assess the correlation between the above parameters with prostate-specific antigen (PSA) levels and Gleason score (GS). Receiver operating characteristic (ROC) curve analysis was used to determine optimal cut-off values for SUVmax, TL-PSMAp, and PSMA-TVp to identify high-risk PCa and compare diagnostic efficacy.

Results

Among 60 patients, 46 were assigned to the HR group and 16 to the LIR group. In all patients, SUVmax, TL-PSMAp, and PSMA-TVp were moderately correlated with pre-treatment PSA values (r = 0.411, p = 0.001; r = 0.663, p < 0.001; and r = 0.549, p < 0.001, respectively). SUVmax and TL-PSMAp were moderately correlated with GS (r = 0.457 and r = 0.448, respectively; p < 0.001), while PSMA-TVp was weakly correlated with GS (r = 0.285, p = 0.027). In the ROC curve analysis, the optimal cut-off values of SUVmax, TL-PSMAp, and PSMA-TVp for identifying high-risk PCa were 9.61, 59.62, and 10.27, respectively, and the areas under the operating curve were 0.828, 0.901, and 0.809, respectively. The sensitivities of SUVmax, TL-PSMAp, and PSMA-TVp were 91.03%, 71.74%, and 63.04%, respectively, and the specificities were 71.43%, 100.00%, and 92.86%, respectively.

Conclusions

TL-PSMAp had a superior ability to identify high-risk PCa. The semi-quantitative parameters of primary tumor on ¹⁸F-PSMA-1007 PET/CT imaging can be an objective imaging reference index to determine PCa risk stratification.

Current progress of nanomedicine for prostate cancer diagnosis and treatment

Prostate cancer (PCa) is the most common new cancer case and the second most fatal malignancy in men. Surgery, endocrine therapy, radiotherapy and chemotherapy are the main clinical treatment options for PCa. However, most prostate cancers can develop into castration-resistant prostate cancer (CRPC), and due to the invasiveness of prostate cancer cells, they become resistant to different treatments and activate tumor-promoting signaling pathways, thereby inducing chemoresistance, radioresistance, ADT resistance, and immune resistance. Nanotechnology, which can combine treatment with diagnostic imaging tools, is emerging as a promising treatment modality in prostate cancer therapy. Nanoparticles can not only promote their accumulation at the pathological site through passive targeting techniques for enhanced permeability and retention (EPR), but also provide additional advantages for active targeting using different ligands. This property results in a reduced drug dose to achieve the desired effect, a longer duration of action within the tumor and fewer side effects on healthy tissues. In addition, nanotechnology can create good synergy with radiotherapy, chemotherapy, thermotherapy, photodynamic therapy and gene therapy to enhance their therapeutic effects with greater scope, and reduce the resistance of prostate cancer. In this article, we intend to review and discuss the latest technologies regarding the use of nanomaterials as therapeutic and diagnostic tools for prostate cancer.

Current Opinion on the Use of Magnetic Resonance Imaging in Staging Prostate Cancer: A Narrative Review

Accurate staging is critical for treatment planning and prognosis in men with prostate Cancer. Prostate magnetic imaging resonance (MRI) may aid in the staging evaluation by verifying organ-confined status, assessing the status of the pelvic lymph nodes, and establishing the local extent of the tumor in patients being considered for therapy. MRI has a high specificity for diagnosing extracapsular extension, and therefore may impact the decision to perform nerve sparing prostatectomy, along with seminal vesicle invasion and lymph node metastases; however, its sensitivity remains limited. Current guidelines vary significantly regarding endorsing the use of MRI for staging locoregional disease. For high-risk prostate cancer, most guidelines recommend cross sectional imaging, including MRI, to evaluate for more extensive disease that may merit change in radiation field, extended androgen deprivation therapy, or guiding surgical planning. Although MRI offers reasonable performance characteristics to evaluate bone metastases, guidelines continue to support the use of bone scintigraphy. Emerging imaging technologies, including coupling positron emission tomography (PET) with MRI, have the potential to improve the accuracy of prostate cancer staging with the use of novel radiotracers.

Clinical Evaluation of (4S)-4-(3-[18F]Fluoropropyl)-L-glutamate (18F-FSPG) for PET/CT Imaging in Patients with Newly Diagnosed and Recurrent Prostate Cancer

PURPOSE

(4S)-4-(3-[¹⁸F]Fluoropropyl)-L-glutamic acid (¹⁸F-FSPG) is a radiopharmaceutical for PET imaging of system x_C ^- activity, which can be upregulated in prostate cancer. We present data on the first evaluation of patients with newly diagnosed or recurrent prostate cancer with this radiopharmaceutical.

EXPERIMENTAL DESIGN

Ten patients with primary and 10 patients with recurrent prostate cancer were enrolled in this prospective multicenter study. After injection of 300 MBq of ¹⁸F-FSPG, three whole-body PET/CT scans were obtained. Visual analysis was compared with step-section histopathology when available as well as other imaging studies and clinical outcomes. Metabolic parameters were measured semiquantitatively. Expression levels of xCT and CD44 were evaluated by IHC for patients with available tissue samples.

RESULTS

¹⁸F-FSPG PET showed high tumor-to-background ratios with a relatively high tumor detection rate on a per-patient (89%) and per-lobe (87%) basis. The sensitivity was slightly higher with imaging at 105 minutes in comparison with 60 minutes. The maximum standardized uptake values (SUV_max) for cancer was significantly higher than both normal (P < 0.005) and benign pathology (P = 0.011), while there was no significant difference between normal and benign pathology (P = 0.120). In the setting of recurrence, agreement with standard imaging was demonstrated in 7 of 9 patients (78%) and 13 of 18 lesions (72%), and revealed true local recurrence in a discordant case. ¹⁸F-FSPG accumulation showed moderate correlation with CD44 expression.

CONCLUSIONS

¹⁸F-FSPG is a promising tumor imaging agent for PET that seems to have favorable biodistribution and high cancer detection rate in patients with prostate cancer. Further studies are warranted to determine the diagnostic value for both initial staging and recurrence, and how it compares with other investigational radiotracers and conventional imaging modalities.

Imaging and Management of Prostate Cancer

Prostate cancer (PCa) is the most common noncutaneous malignancy in men and the second leading cause of cancer related death in the United States. Men with clinical suspicion of PCa undergo tissue sampling and based on features including the Gleason score, Prostate Specific antigen (PSA) levels and clinical tumor (T) stage, patients are risk stratified into 6 major groups based on National Comprehensive Cancer Network (NCCN) guidelines. This forms the basis for deciding imaging and management. Active surveillance is the preferred approach for less aggressive tumors. Surgery or radiation +/- androgen deprivation therapy continue to be the primary treatment options for localized disease. Imaging plays a critical role in the diagnosis, staging and management of PCa. Multiparametric magnetic resonance imaging (mpMRI) is currently the imaging modality of choice for locoregional staging. MRI, computed tomography and bone scan remain the preferred modalities for evaluation of nodal, soft tissue, and bone metastases, respectively. Advanced positron emission tomography imaging using novel radiotracers are being developed but are not yet integrated in the diagnostic guidelines for initial staging. In this review, we will discuss the imaging and treatment algorithms based on the NCCN risk groups, describe the utility of individual modalities, review Prosate Imaging and Reporting and Data System (PIRADS) version 2.1 for the reporting of mpMRI of the prostate.

Combined analysis of CRMP4 methylation levels and CAPRA-S score predicts metastasis and outcomes in prostate cancer patients

The present study analyzed the predictive value of combined analysis of collapsin response mediator protein 4 (CRMP4) methylation levels and the Cancer of the Prostate Risk Assessment (CAPRA-S) Postsurgical score of patients who required adjuvant hormone therapy (AHT) after radical prostatectomy (RP). We retrospectively analyzed 305 patients with prostate cancer (PCa) who received RP and subsequent androgen deprivation therapy (ADT). Two hundred and thirty patients with clinically high-risk PCa underwent immediate ADT, and 75 patients with intermediate risk PCa underwent deferred ADT. CRMP4 methylation levels in biopsies were determined, and CAPRA-S scores were calculated. In the deferred ADT group, the values of the hazard ratios for tumor progression and cancer-specific mortality (CSM) in patients with ≥15% CRMP4 methylation were 6.81 (95% CI: 2.34–19.80) and 12.83 (95% CI: 2.16–26.10), respectively. Receiver-operating characteristic curve analysis indicated that CRMP4 methylation levels ≥15% served as a significant prognostic marker of tumor progression and CSM. In the immediate ADT group, CAPRA-S scores ≥6 and CRMP4 methylation levels ≥15% were independent predictors of these outcomes (uni- and multi-variable Cox regression analyses). The differences in the 5-year progression-free survival between each combination were statistically significant. Combining CAPRA-S score and CRMP4 methylation levels improved the area under the curve compared with the CRMP4 or CAPRA-S model. Therefore, CRMP4 methylation levels ≥15% were significantly associated with a poor prognosis and their combination with CAPRA-S score accurately predicted tumor progression and metastasis for patients requiring AHT after RP.

Multiparametric whole-body 3.0-T MRI in newly diagnosed intermediate- and high-risk prostate cancer: diagnostic accuracy and interobserver agreement for nodal and metastatic staging

OBJECTIVES

To determine the diagnostic accuracy and interobserver concordance of whole-body (WB)-MRI, vs. 99mTc bone scintigraphy (BS) and 18fluoro-ethyl-choline (18F-choline) PET/CT for the primary staging of intermediate/high-risk prostate cancer.

METHODS

An institutional review board approved prospective cohort study carried out between July 2012 and November 2015, whereby 56 men prospectively underwent 3.0-T multiparametric (mp)-WB-MRI in addition to BS (all patients) ± 18F-choline PET/CT (33 patients). MRI comprised pre- and post-contrast modified Dixon (mDixon), T2-weighted (T2W) imaging, and diffusion-weighted imaging (DWI). Patients underwent follow-up mp-WB-MRI at 1 year to derive the reference standard. WB-MRIs were reviewed by two radiologists applying a 6-point scale and a locked sequential read (LSR) paradigm for the suspicion of nodal (N) and metastatic disease (M1a and M1b).

RESULTS

The mean sensitivity/specificity of WB-MRI for N1 disease was 1.00/0.96 respectively, compared with 1.00/0.82 for 18F-choline PET/CT. The mean sensitivity and specificity of WB-MRI, 18F-choline PET/CT, and BS were 0.90/0.88, 0.80/0.92, and 0.60/1.00 for M1b disease. ROC-AUC did not show statistically significant improvement for each component of the LSR; mean ROC-AUC 0.92, 0.94, and 0.93 (p < 0.05) for mDixon + DWI, + T2WI, and + contrast respectively. WB-MRI had an interobserver concordance (κ) of 0.79, 0.68, and 0.58 for N1, M1a, and M1b diseases respectively.

CONCLUSIONS

WB-MRI provides high levels of diagnostic accuracy for both nodal and metastatic bone disease, with higher levels of sensitivity than BS for metastatic disease, and similar performance to 18F-choline PET/CT. T2 and post-contrast mDixon had no significant additive value above a protocol comprising mDixon and DWI alone.

KEY POINTS

• A whole-body MRI protocol comprising unenhanced mDixon and diffusion-weighted imaging provides high levels of diagnostic accuracy for the primary staging of intermediate- and high-risk prostate cancer. • The diagnostic accuracy of whole-body MRI is much higher than that of bone scintigraphy, as currently recommended for clinical use. • Staging using WB-MRI, rather than bone scintigraphy, could result in better patient stratification and treatment delivery than is currently provided to patients worldwide.

Patient-specific 3D printed and augmented reality kidney and prostate cancer models: impact on patient education

Background

Patient-specific 3D models are being used increasingly in medicine for many applications including surgical planning, procedure rehearsal, trainee education, and patient education. To date, experiences on the use of 3D models to facilitate patient understanding of their disease and surgical plan are limited. The purpose of this study was to investigate in the context of renal and prostate cancer the impact of using 3D printed and augmented reality models for patient education.

Methods

Patients with MRI-visible prostate cancer undergoing either robotic assisted radical prostatectomy or focal ablative therapy or patients with renal masses undergoing partial nephrectomy were prospectively enrolled in this IRB approved study (n = 200). Patients underwent routine clinical imaging protocols and were randomized to receive pre-operative planning with imaging alone or imaging plus a patient-specific 3D model which was either 3D printed, visualized in AR, or viewed in 3D on a 2D computer monitor. 3D uro-oncologic models were created from the medical imaging data. A 5-point Likert scale survey was administered to patients prior to the surgical procedure to determine understanding of the cancer and treatment plan. If randomized to receive a pre-operative 3D model, the survey was completed twice, before and after viewing the 3D model. In addition, the cohort that received 3D models completed additional questions to compare usefulness of the different forms of visualization of the 3D models. Survey responses for each of the 3D model groups were compared using the Mann-Whitney and Wilcoxan rank-sum tests.

Results

All 200 patients completed the survey after reviewing their cases with their surgeons using imaging only. 127 patients completed the 5-point Likert scale survey regarding understanding of disease and surgical procedure twice, once with imaging and again after reviewing imaging plus a 3D model. Patients had a greater understanding using 3D printed models versus imaging for all measures including comprehension of disease, cancer size, cancer location, treatment plan, and the comfort level regarding the treatment plan (range 4.60–4.78/5 vs. 4.06–4.49/5, p < 0.05).

Conclusions

All types of patient-specific 3D models were reported to be valuable for patient education. Out of the three advanced imaging methods, the 3D printed models helped patients to have the greatest understanding of their anatomy, disease, tumor characteristics, and surgical procedure.

ACR Appropriateness Criteria® Prostate Cancer-Pretreatment Detection, Surveillance, and Staging

Despite the frequent statement that "most men die with prostate cancer, not of it," the reality is that prostate cancer is second only to lung cancer as a cause of death from malignancy in American men. The primary goal during baseline evaluation of prostate cancer is disease characterization, that is, establishing disease presence, extent (local and distant), and aggressiveness. Prostate cancer is usually diagnosed after the finding of a suspicious serum prostate-specific antigen level or digital rectal examination. Tissue diagnosis may be obtained by transrectal ultrasound-guided biopsy or MRI-targeted biopsy. The latter requires a preliminary multiparametric MRI, which has emerged as a powerful and relatively accurate tool for the local evaluation of prostate cancer over the last few decades. Bone scintigraphy and CT are primarily used to detect bone and nodal metastases in patients found to have intermediate- or high-risk disease at biopsy. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Management of Patients with Advanced Prostate Cancer: The Report of the Advanced Prostate Cancer Consensus Conference APCCC 2017

BACKGROUND

In advanced prostate cancer (APC), successful drug development as well as advances in imaging and molecular characterisation have resulted in multiple areas where there is lack of evidence or low level of evidence. The Advanced Prostate Cancer Consensus Conference (APCCC) 2017 addressed some of these topics.

OBJECTIVE

To present the report of APCCC 2017.

DESIGN, SETTING, AND PARTICIPANTS

Ten important areas of controversy in APC management were identified: high-risk localised and locally advanced prostate cancer; "oligometastatic" prostate cancer; castration-naïve and castration-resistant prostate cancer; the role of imaging in APC; osteoclast-targeted therapy; molecular characterisation of blood and tissue; genetic counselling/testing; side effects of systemic treatment(s); global access to prostate cancer drugs. A panel of 60 international prostate cancer experts developed the program and the consensus questions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The panel voted publicly but anonymously on 150 predefined questions, which have been developed following a modified Delphi process.

RESULTS AND LIMITATIONS

Voting is based on panellist opinion, and thus is not based on a standard literature review or meta-analysis. The outcomes of the voting had varying degrees of support, as reflected in the wording of this article, as well as in the detailed voting results recorded in Supplementary data.

CONCLUSIONS

The presented expert voting results can be used for support in areas of management of men with APC where there is no high-level evidence, but individualised treatment decisions should as always be based on all of the data available, including disease extent and location, prior therapies regardless of type, host factors including comorbidities, as well as patient preferences, current and emerging evidence, and logistical and economic constraints. Inclusion of men with APC in clinical trials should be strongly encouraged. Importantly, APCCC 2017 again identified important areas in need of trials specifically designed to address them.

PATIENT SUMMARY

The second Advanced Prostate Cancer Consensus Conference APCCC 2017 did provide a forum for discussion and debates on current treatment options for men with advanced prostate cancer. The aim of the conference is to bring the expertise of world experts to care givers around the world who see less patients with prostate cancer. The conference concluded with a discussion and voting of the expert panel on predefined consensus questions, targeting areas of primary clinical relevance. The results of these expert opinion votes are embedded in the clinical context of current treatment of men with advanced prostate cancer and provide a practical guide to clinicians to assist in the discussions with men with prostate cancer as part of a shared and multidisciplinary decision-making process.

18F-Fluorocholine PET Whole-Body MRI in the Staging of High-Risk Prostate Cancer

OBJECTIVE

The purpose of this study was to determine whether integrated ¹⁸F-fluorocholine (FCH) PET whole-body MRI (PET/WBMRI) depicts lymph node and distant metastases in patients with high-risk prostate cancer more frequently than does conventional staging.

SUBJECTS AND METHODS

A prospective study included 58 patients with untreated high-risk prostate cancer. After conventional staging (CT and bone scintigraphy), patients underwent FCH PET/WBMRI (n = 10) or FCH PET/CT and WBMRI (n = 48). Metastatic sites and disease stage were recorded for each modality (conventional imaging, PET, WBMRI, and PET/WBMRI) and compared with a standard of reference (histopathologic examination, imaging, and clinical follow-up) and early clinical outcomes.

RESULTS

In the detection of metastases, PET had significantly higher sensitivity (72/77 [93.5%]) than conventional imaging (49/77 [63.6%]; p < 0.001) and WBMRI (56/77 [72.7%]; p = 0.002). There was a trend toward improved detection with PET/WBMRI (77/77 [100%]) compared with PET alone (p = 0.059). For correct NM staging, PET and PET/WBMRI performed better than conventional imaging (p = 0.002) and WBMRI (p = 0.008). Twelve of 56 patients (21.4%) had early biochemical failure after radical treatment (median, 7 months; range, 1-20 months). This rate was higher for patients with M1a or M1b disease at PET/WBMRI than for others, but this finding did not reach statistical significance (4/8 [50%] vs 8/48 [16.7%]; p = 0.055).

CONCLUSION

In patients with high-risk prostate cancer, FCH PET and FCH PET/WBMRI depict significantly more metastatic lesions than do conventional imaging and WBMRI. Stage determined with PET/WBMRI may correlate with early outcomes.

Using Imaging to Predict Treatment Response in Genitourinary Malignancies

CONTEXT

Over the previous2 decades, there have been numerous advancements in the diagnostic evaluation, therapeutic management, and postoperative assessment of genitourinary malignancies.

OBJECTIVE

To present a review of current and novel imaging modalities and their utility in the assessment of therapeutic response in the systemic management of renal, testicular, and prostate cancers.

EVIDENCE ACQUISITION

A PubMed/Medline search of the current published literature inclusive of prospective and retrospective original research, systematic reviews, and meta-analyses was conducted evaluating imaging modalities for renal cell carcinoma, prostate cancer, and testicular cancer. All relevant literature was individually reviewed and summarized to provide a concise description of the currently available imaging modalities and their efficacy in assessing treatment response of the genitourinary malignancies targeted in this review.

EVIDENCE SYNTHESIS

Conventional imaging techniques play a pivotal role in predicting the treatment response of genitourinary malignancies and have, therefore, been incorporated into clinical guidelines. Advancements in imaging technology have led to increased utilization for prognostication of a genitourinary cancer's response to therapy.

CONCLUSIONS

A good understanding of current recommended imaging techniques to evaluate treatment response in genitourinary malignancies is of paramount importance for today's clinician, who faces increasing treatment modalities.

PATIENT SUMMARY

In this review, we summarize available imaging modalities in the evaluation of treatment response in kidney, prostate, or testicular tumors. We believe that a good understanding of current imaging modalities is of paramount importance for healthcare providers treating these cancers.

A Prospective Study Comparing 99mTc-Hydroxyethylene-Diphosphonate Planar Bone Scintigraphy and Whole-Body SPECT/CT with 18F-Fluoride PET/CT and 18F-Fluoride PET/MRI for Diagnosing Bone Metastases

We prospectively evaluated and compared the diagnostic performance of ^99mTc-hydroxyethylene-diphosphonate (^99mTc-HDP) planar bone scintigraphy (pBS), ^99mTc-HDP SPECT/CT, ¹⁸F-NaF PET/CT, and ¹⁸F-NaF PET/MRI for the detection of bone metastases. Methods: One hundred seventeen patients with histologically proven malignancy referred for clinical pBS were prospectively enrolled. pBS and whole-body SPECT/CT were performed followed by ¹⁸F-NaF PET/CT within 9 d. ¹⁸F-NaF PET/MRI was also performed in 46 patients. Results: Bone metastases were confirmed in 16 patients and excluded in 101, which was lower than expected. The number of equivocal scans was significantly higher for pBS than for SPECT/CT and PET/CT (18 vs. 5 and 6, respectively; P = 0.004 and 0.01, respectively). When equivocal readings were excluded, no statistically significant difference in sensitivity, specificity, positive predictive value, negative predictive value, or overall accuracy were found when comparing the different imaging techniques. In the per-patient analysis, equivocal scans were either assumed positive for metastases ("pessimistic analysis") or assumed negative for metastases ("optimistic analysis"). The percentages of misdiagnosed patients for the pessimistic analysis were 21%, 15%, 9%, and 7% for pBS, SPECT/CT, PET/CT, and PET/MRI, respectively. Corresponding figures for the optimistic analysis were 9%, 12%, 5%, and 7%. In those patients identified as having bone metastases according to the reference standard, SPECT/CT, ¹⁸F-NaF PET/CT, and PET/MRI detected additional lesions compared with pBS in 31%, 63%, and 71%, respectively. Conclusion:¹⁸F-NaF PET/CT and whole-body SPECT/CT resulted in a significant reduction of equivocal readings compared with pBS, which implies an improved diagnostic confidence. However, the clinical benefit of using, for example, ¹⁸F-NaF PET/CT or PET/MRI as compared with SPECT/CT and pBS in this patient population with a relatively low prevalence of bone metastases (14%) is likely limited. This conclusion is influenced by the low prevalence of patients with osseous metastases. There may well be significant differences in the sensitivity of SPECT/CT, PET/CT, and PET/MRI compared with pBS, but a larger patient population or a patient population with a higher prevalence of bone metastases would have to be studied to demonstrate this.

Current Status of Prostate-Specific Membrane Antigen Targeting in Nuclear Medicine: Clinical Translation of Chelator Containing Prostate-Specific Membrane Antigen Ligands Into Diagnostics and Therapy for Prostate Cancer

The prostate-specific membrane antigen (PSMA) is expressed by approximately 90% of prostate carcinomas. The expression correlates with unfavorable prognostic factors, such as a high Gleason score, infiltrative growth, metastasis, and hormone-independence. The high specificity, especially in the undifferentiated stage, makes it an excellent target for diagnosis and therapy. Therefore, antibodies and small molecule inhibitors have been developed for imaging and therapy. In 2011 PSMA-11, a ligand that consists of the Glu-urea-motif and the chelator HBED-CC, which can be exclusively radiolabeled with (68)Ga for PET imaging, presented the clinical breakthrough for prostate cancer diagnostics. In two large diagnostic studies (n = 319 and n = 248) PET/CT with PSMA-11 successfully localized the recurrent tumor in approximately 90% of patients with biochemical relapse. Integrating PSMA-PET/CT into the planning phase of radiotherapy, the treatment concept is changed in 30%-50% of the patients. The combination of the Glu-urea-motif with DOTA, which can be labeled with several diagnostic and therapeutic radionuclides, opened new avenues for therapeutic usage of the small-molecule PSMA ligands. In the beginning of 2016, there are four confirmative reports (n = 19, n = 24, n = 30, and n = 56) from four different centers reporting a PSA response in approximately 70% of patients treated with (177)Lu-labeled PSMA ligands. In conclusion, the data available up to now indicate a widespread use of PSMA ligands for diagnostic applications with respect to staging, detection of recurrence, or metastases in patients with rising tumor markers and for therapy in case of failure of guideline-compliant treatment.

Evaluation of sHLA-G levels in serum of patients with prostate cancer identify as a potential of tumor marker

Prostate cancer is the most common cancer type in men and is the second cause of death, due to cancer, in patients over 50, after lung cancer. Prostate specific antigen (PSA) is a widely used tumor marker for prostate cancer. Recently, PSA is discovered in non-prostatic cancer tissues in men and women raising doubts about its specificity for prostatic tissues. PSA exists in low serum level in healthy men and in higher levels in many prostate disorders, including prostatitis and prostate cancer. Thus, a supplementary tumor marker is needed to accurately diagnose the cancer and to observe the patient after treatment. Recently, soluble human leukocyte antigen-G (sHLA-G) has been introduced as a new tumor marker for different cancer types, including colorectal, breast, lung, and ovary. The present descriptive-experimental study was carried out including patients with malignant prostate tumor, patients with benign prostate tumor, and a group of health men as the control group, as judged by an oncologist as well as a pathologist. After sterile blood sampling, sHLA-G was measured by enzyme-linked immunosorbent assay in each group. The data was then analyzed using one-way ANOVA. P≤0.05 was considered as statistically significant. The results showed that the mean of sHLA-G level was high in patients. Also, it was found that there was a significant difference in sHLA serum level between the three groups. The data revealed that sHLA-G can be a novel supplementary tumor marker in addition to PSA to diagnose prostate cancer.

Disparities in staging prostate magnetic resonance imaging utilization for nonmetastatic prostate cancer patients undergoing definitive radiation therapy

PURPOSE

There is growing evidence supporting incorporating multiparametric (mp) magnetic resonance imaging (MRI) scans into risk stratification, active surveillance, and treatment paradigms for prostate cancer. The purpose of our study was to determine whether demographic disparities exist in staging MRI utilization for prostate cancer patients.

METHODS AND MATERIALS

An institutional database of 705 nonmetastatic prostate cancer patients treated with radiation therapy from 2005 through 2013 was used to identify patients undergoing versus not undergoing pretreatment diagnostic prostate mpMRI. Uni- and multivariable logistic regression evaluated the relationship of clinical and demographic characteristics with MRI utilization.

RESULTS

All demographic variables assessed, except the other race category, were significantly associated with MRI utilization (all P < .05), including age (odds ratio [OR], 0.92), black race (OR, 0.51), poverty (OR, 0.53), closer distance to radiation facility (OR, 1.79), and nonprivate primary insurance (OR, 0.57) on univariable analysis, while clinical stage T3 (OR, 3.37) was the only clinical characteristic. On multivariable analysis stratified by D'Amico risk group, age remained significant across all risk groups, whereas the black versus white racial (OR, 0.21; 95% confidence interval, 0.08-0.55) and nonprivate versus private insurance type (OR, 0.37; 95% confidence interval, 0.16-0.86) disparities persisted in the low-risk group. Clinical stage T3 remained associated in the high-risk group. For race specifically, the percentages of whites, blacks, and others undergoing MRI in the overall cohort and by risk group were, respectively: overall, 80% (343/427), 68% (156/231), and 85% (40/47); low risk, 86%, 56%, and 63%; intermediate risk, 79%, 72%, and 95%; and high risk, 72%, 72%, and 100%.

CONCLUSIONS

In this urban, academic center cohort, older patients across all risk groups and black or nonprivate insurance patients in the low risk group were less likely to undergo staging prostate MRI scans. Further research should investigate these differences to ensure equitable utilization across all demographic groups considering the burden of prostate cancer disparities.

Molecular mechanisms underlying resistance to androgen deprivation therapy in prostate cancer

Prostate cancer (PCa) is the most widely diagnosed male cancer in the Western World and while low- and intermediate-risk PCa patients have a variety of treatment options, metastatic patients are limited to androgen deprivation therapy (ADT). This treatment paradigm has been in place for 75 years due to the unique role of androgens in promoting growth of prostatic epithelial cells via the transcription factor androgen receptor (AR) and downstream signaling pathways. Within 2 to 3 years of ADT, disease recurs-at which time, patients are considered to have castration-recurrent PCa (CR-PCa). A universal mechanism by which PCa becomes resistant to ADT has yet to be discovered. In this review article, we discuss underlying molecular mechanisms by which PCa evades ADT. Several major resistance pathways center on androgen signaling, including intratumoral and adrenal androgen production, AR-overexpression and amplification, expression of AR mutants, and constitutively-active AR splice variants. Other ADT resistance mechanisms, including activation of glucocorticoid receptor and impairment of DNA repair pathways are also discussed. New therapies have been approved for treatment of CR-PCa, but increase median survival by only 2-8 months. We discuss possible mechanisms of resistance to these new ADT agents. Finally, the practicality of the application of "precision oncology" to this continuing challenge of therapy resistance in metastatic or CR-PCa is examined. Empirical validation and clinical-based evidence are definitely needed to prove the superiority of "precision" treatment in providing a more targeted approach and curative therapies over the existing practices that are based on biological "cause-and-effect" relationship.

Molecular imaging of fibrosis using a novel collagen-binding peptide labelled with 99mTc on SPECT/CT

Fibrosis, closely related to chronic various diseases, is a pathological process characterised by the accumulation of collagen (largely collagen type I). Non-invasive methods are necessary for the diagnosis and follow-up of fibrosis. This study aimed to develop a collagen-targeted probe for the molecular imaging of fibrosis. We identified CPKESCNLFVLKD (CBP1495) as an original collagen-binding peptide using isothermal titration calorimetry and enzyme-linked immunosorbent assay. CBP1495 effectively bound to collagen type I (K _d = 861 nM) and (GPO)₉ (K _d = 633 nM), a collagen mimetic peptide. Western blot and histochemistry validated CBP1495 targeting collagen in vitro and ex vivo. (Gly-(D)-Ala-Gly-Gly) was introduced to CBP1495 for coupling ^99mTc. Labelling efficiency of ^99mTc-CBP1495 was 95.06 ± 1.08 %. The physico-chemical properties, tracer kinetics and biodistribution of ^99mTc-CBP1495 were carried out, and showed that the peptide stably chelated ^99mTc in vitro and in vivo. SPECT/CT imaging with ^99mTc-CBP1495 was performed in rat fibrosis models, and revealed that ^99mTc-CBP1495 significantly accumulated in fibrotic lungs or livers of rats. Finally, ^99mTc-CBP1495 uptake and hydroxyproline (Hyp), a specific amino acid of collagen, were quantitatively analysed. The results demonstrated that ^99mTc-CBP1495 uptake was positvely correlated with Hyp content in lungs (P < 0.0001, r ² = 0.8266) or livers (P < 0.0001, r ² = 0.7581). Therefore, CBP1495 is a novel collagen-binding peptide, and ^99mTc-labelled CBP1495 may be a promising radiotracer for the molecular imaging of fibrosis.

Use of dual-phase contrast computed tomography for evaluation of the normal canine male genital tract

OBJECTIVES

To evaluate the use of dual-phase contrast-enhanced computed tomography for the depiction of the features of the male genital tract, highlighting differences between entire and neutered dogs.

METHODS

Computed tomography exams of 23 entire and 23 neutered male dogs with no history of urogenital disease were included in this retrospective study, with exams acquired pre-, 30 and 98·9 ±27·4 seconds after intravenous contrast administration. The genital structures were subjectively evaluated for visibility, contrast enhancement and enhancement pattern and differences between entire and neutered dogs were described. Objective measurements of attenuation and size of the prostatic tissue were acquired.

RESULTS

The root, body and glans of the penis could be evaluated in all dogs and appeared larger in entire dogs, though objective measurements could not be reliably made because these structures are small and curved. There was contrast enhancement of the cavernous structures, most reliably in the bulb and corpus spongiosum and most frequently in entire dogs in the delayed post-contrast phase. In entire dogs, the small testicular vessels most commonly had a vermiform shape in the early post-contrast phase, and a homogeneous appearance in the delayed phase. Sternal recumbency with the coxofemoral joints extended improved visibility of the genital structures.

CLINICAL SIGNIFICANCE

Dual-phase contrast-enhanced computed tomography is useful for depiction of the structures of the male genital tract, with the early phase especially highlighting the vascular and the delayed phase the cavernous structures.

18F Fluorocholine Dynamic Time-of-Flight PET/MR Imaging in Patients with Newly Diagnosed Intermediate- to High-Risk Prostate Cancer: Initial Clinical-Pathologic Comparisons

Purpose To investigate the initial clinical value of fluorine 18 (¹⁸F) fluorocholine (FCH) dynamic positron emission tomography (PET)/magnetic resonance (MR) imaging by comparing its parameters with clinical-pathologic findings in patients with newly diagnosed intermediate- to high-risk prostate cancer (PCa) who plan to undergo radical prostatectomy. Materials and Methods The institutional review board approved the study protocol, and informed written consent was obtained from all subjects for this HIPAA-compliant study. Twelve men (mean age ± standard deviation, 61.7 years ± 8.4; range, 46-74 years) with untreated intermediate- to high-risk PCa characterized according to Cancer of the Prostate Risk Assessment (CAPRA) underwent preoperative FCH dynamic PET/MR imaging followed by radical prostatectomy between April and November 2015. PET/MR imaging parameters including average and maximum K1 (delivery rate constant) and standardized uptake values (SUVs) and Prostate Imaging Reporting and Data System (PI-RADS) version 2 scores were measured and compared with clinical-pathologic characteristics. For statistical analysis, the Spearman rank correlation and Mann-Whitney U tests were performed. Results Of the PET parameters, maximum SUV of primary tumors showed significant correlations with several clinical-pathologic parameters including serum prostate-specific antigen level (ρ = 0.71, P = .01), pathologic stage (ρ = 0.59, P = .043), and postsurgical CAPRA score (ρ = 0.72, P = .008). The overall PI-RADS score showed significant correlations with pathologic tumor volume (ρ = 0.81, P < .001), percentage of tumor cells with Gleason scores greater than 3 (ρ = 0.59, P = .02), and postsurgical CAPRA score (ρ = 0.58, P = .046). The high-risk postsurgical CAPRA score patient group had a significantly higher maximum SUV than did the intermediate-risk group. Combined PET and MR imaging showed improved sensitivity (88%) for prediction of pathologic extraprostatic extension compared with that with MR imaging (50%) and PET (75%) performed separately. Conclusion Maximum SUVs and PI-RADS scores from FCH PET/MR imaging show good correlation with clinical-pathologic characteristics, such as postsurgical CAPRA score, which are related to prognosis in patients with newly diagnosed intermediate- to high-risk PCa. ^© RSNA, 2016 Online supplemental material is available for this article.

Cytoreductive radical prostatectomy in metastatic prostate cancer: Does it really make sense?

PURPOSE

Surgical removal of the primary tumor in metastatic prostate cancer (mPCa) is becoming a hotly debated issue. The purpose of this review was to summarize the current knowledge on cytoreductive radical prostatectomy (cRP) in this setting.

MATERIALS AND METHODS

We performed a non-systematic Medline/PubMed literature search of articles published in the field between January 2000 and April 2015.

RESULTS

Cytoreductive surgery has demonstrated its benefit in various malignancies with a solid biological rationale to justify its assessment in mPCa. cRP appears as a safe and feasible procedure in expert hands and well-selected patients. A growing body of evidence suggests a survival benefit for patients undergoing cRP as a part of a multimodal approach compared to those treated with systemic treatment alone. Nevertheless, little is known about the best clinical and tumor characteristics for the selection of patients most likely to benefit from cRP. The current literature is based on retrospective studies with small cohorts and limited follow-up or large uncontrolled population-based studies.

CONCLUSIONS

Data from various other malignancies together with the biological rationale and preliminary results in PCa suggest that cytoreductive surgery may be an option in some mPCa patients. The lack of randomized controlled trials and the low level of evidence in the current literature preclude any firms conclusion on the benefit of cRP in mPCa. Ongoing phase II and future phase III studies are mandatory to define the exact role of cRP in mPCa and to identify the patients who are most likely to benefit from cRP.

Improvement of Prostate Cancer Diagnosis by Detecting PSA Glycosylation-Specific Changes

New markers based on PSA isoforms have recently been developed to improve prostate cancer (PCa) diagnosis. However, novel approaches are still required to differentiate aggressive from non-aggressive PCa to improve decision making for patients.

PSA glycoforms have been shown to be differentially expressed in PCa. In particular, changes in the extent of core fucosylation and sialylation of PSA N-glycans in PCa patients compared to healthy controls or BPH patients have been reported. The objective of this study was to determine these specific glycan structures in serum PSA to analyze their potential value as markers for discriminating between BPH and PCa of different aggressiveness.

In the present work, we have established two methodologies to analyze the core fucosylation and the sialic acid linkage of PSA N-glycans in serum samples from BPH (29) and PCa (44) patients with different degrees of aggressiveness. We detected a significant decrease in the core fucose and an increase in the α2,3-sialic acid percentage of PSA in high-risk PCa that differentiated BPH and low-risk PCa from high-risk PCa patients. In particular, a cut-off value of 0.86 of the PSA core fucose ratio, could distinguish high-risk PCa patients from BPH with 90% sensitivity and 95% specificity, with an AUC of 0.94. In the case of the α2,3-sialic acid percentage of PSA, the cut-off value of 30% discriminated between high-risk PCa and the group of BPH, low-, and intermediate-risk PCa with a sensitivity and specificity of 85.7% and 95.5%, respectively, with an AUC of 0.97. The latter marker exhibited high performance in differentiating between aggressive and non-aggressive PCa and has the potential for translational application in the clinic.

A urologist's perspective on prostate cancer imaging: past, present, and future

Prostate cancer is unique in that unlike other solid organ malignancies, only recently has imaging been employed to routinely detect and localize disease. The introduction of transrectal ultrasound was a significant development, transitioning digitally guided prostate biopsies to ultrasound guidance. The arrival of multiparametric MRI has become the next major step, transforming the way Urologist's diagnose, stage, and treat prostate cancer. Recent recommendations against PSA screening have changed the landscape of urologic oncology with the changing needs being reflected in the initiation of additional robust imaging techniques at different time points in prostate cancer care. The current review aims to provide a clinical perspective in the history, current standard of care, and novel imaging modalities in the evaluation of prostate cancer.

Knockdown of prostaglandin reductase 1 (PTGR1) suppresses prostate cancer cell proliferation by inducing cell cycle arrest and apoptosis

Chemoresistance is a serious problem for the treatment of androgen-independent prostate cancer (PC). The underlying molecular mechanisms by which androgen-independent PC cells acquire the capacity to proliferate remain largely unclear. The aim of this study was to investigate the biological role of prostaglandin reductase 1 (PTGR1) in prostate cancer. Data from the Oncomine database showed that PTGR1 is commonly upregulated in PC tissue in comparison to corresponding normal controls. Two PTGR1-specific short hairpin RNA (shRNA) sequences were used to block the expression of PTGR1 via a lentivirus-mediated system in the androgen-independent PC cell lines DU145 and PC 3. Functional analysis revealed that knockdown of PTGR1 significantly inhibited proliferation and colony formation by PC cells. The inhibition of cell proliferation was related to arrest of the cell cycle in the G0/G1 phase and increased apoptosis in response to PTGR1 knockdown as indicated by flow cytometry. PTGR1 silencing was found to mechanically enhance the expression of p21, caspase 3, and cleaved PARP and to decrease the level of cyclin D1. In conclusion, PTGR1 plays an essential role in PC cells and may be a potential therapeutic target for PC.

Transcription Factor HBP1 Enhances Radiosensitivity by Inducing Apoptosis in Prostate Cancer Cell Lines

Radiotherapy for prostate cancer has been gradually carried out in recent years; however, acquired radioresistance often occurred in some patients after radiotherapy. HBP1 (HMG-box transcription factor 1) is a transcriptional inhibitor which could inhibit the expression of dozens of oncogenes. In our previous study, we showed that the expression level of HBP1 was closely related to prostate cancer metastasis and prognosis, but the relationship between HBP1 and radioresistance for prostate cancer is largely unknown. In this study, the clinical data of patients with prostate cancer was compared, and the positive correlation was revealed between prostate cancer brachytherapy efficacy and the expression level of HBP1 gene. Through research on prostate cancer cells in vitro, we found that HBP1 expression levels were negatively correlated with oncogene expression levels. Furthermore, HBP1 overexpression could sensitize prostate cancer cells to radiation and increase apoptosis in prostate cancer cells. In addition, animal model was employed to analyze the relationship between HBP1 gene and prostate cancer radiosensitivity in vivo; the result showed that knockdown of HBP1 gene could decrease the sensitivity to radiation of xenograft. These studies identified a specific molecular mechanism underlying prostate cancer radiosensitivity, which suggested HBP1 as a novel target in prostate cancer radiotherapy.