Specific Membrane Antigen Positron Emission Research Articles

Imaging of Prostate Specific Membrane Antigen Targeted Radiotracers for the Detection of Prostate Cancer Biochemical Recurrence after Definitive Therapy: A Systematic Review and Meta-Analysis.

Prostate specific membrane antigen targeted radiotracers are promising agents for imaging patients with prostate cancer biochemical recurrence after definitive therapy. We report the results of a systematic review and meta-analysis of the detection of biochemical recurrence after definitive therapy for prostate cancer stratified by prostate specific antigen levels and using prostate specific membrane antigen targeted radiotracers. According to the Preferred Reporting Items for Systematic reviews and Meta-Analysis Diagnostic Test Accuracy guidelines, we searched for articles in PubMed® and EMBASE® databases in our systematic review from 2012 to July 2018. Studies evaluating men with prostate cancer biochemical recurrence after definitive therapy and without known metastatic disease who underwent prostate specific membrane antigen positron emission tomography/computerized tomography to detect recurrent disease were included in analysis. The risk of bias and applicability concerns were assessed by QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies 2). Statistical heterogeneity was assessed with the Cochrane Q and an I2 estimate. The reference standard was pathology findings, followup imaging or a prostate specific antigen decline after salvage treatment. We calculated pooled estimates and the 95% CI around the prevalence of a positive examination in the study population using a random effects model. A total of 5,113 patients in 43 studies were included in this systematic review. Of the studies 15 (34.8%) were prospective, 3 (6.9%) were multi-institutional and the remainder were done at a single center. A total of 18 studies (41.8%) were done in subjects after radical prostatectomy, 2 (4.6%) were in subjects after radiotherapy and 23 (53.5%) were in subjects after radical prostatectomy and radiotherapy. Median prostate specific antigen was 1.6 ng/ml (IQR 0.7-4.4) and median subject age was 68 years (IQR 67-70). Of the 43 studies 33 (76.7%) evaluated 68Ga prostate specific membrane antigen-11 (Ga-HBED-CC) positron emission tomography/computerized tomography. The pooled detection rate was 70.2% (95% CI 65.0-75.4) in the entire cohort. For prostate specific antigen less than 0.5, 0.5 to 0.9, 1 to 1.9 and 2 ng/ml or greater the pooled detection rate was 44.9% (95% CI 36.0-53.9), 61.3% (95% CI 52.3-70.3), 78.2% (95% CI 70.8-85.6) and 93.9% (95% CI 92.0-95.8), respectively. A reference standard was confirmed to be positive in 684 of the 715 patients (95.7%). There were significant study heterogeneity and publication biases (p <0.01). Prostate specific membrane antigen targeted radiotracers are likely effective to detect biochemically recurrent prostate cancer at low prostate specific antigen levels. However, existing studies are limited by retrospective design, limited reference standards, publication bias and a lack of interagent comparison.

MP09-14 HYBRID PSMA PET/MRI FOR PRIMARY STAGING IN PRESUMED LOCALISED PROSTATE CANCER: A CONTEMPORARY, TERTIARY HOSPITAL SERIES

INTRODUCTION AND OBJECTIVES:Hybrid (68) Ga-labelled Prostate Specific Membrane Antigen (PSMA) positron emission tomography (PET) with magnetic resonance imaging (MRI) serves to combine detailed res...

PD17-04 DIAGNOSTIC EFFICACY OF 18F-RHPSMA7 POSITRON EMISSION TOMOGRAPHY FOR N-STAGING OF PATIENTS WITH HIGH RISK PRIMARY PROSTATE CANCER

INTRODUCTION AND OBJECTIVES:68Ga-prostate specific membrane antigen (PSMA) positron emission tomography (PET) has become a common method for primary staging of prostate cancer in Europe. However, 18F-labeled PSMA ligands are increasingly being used owing to their favorable half-life, large batch production and lower positron range compared with 68Ga-labeled counterparts. Radiohybrid PSMA (rhPSMA) ligands are a new class of theranostic PSMA-targeting agents that feature the fast synthesis associated with 18F while allowing labeling with radiometals. This retrospective analysis investigates the efficacy of 18F-rhPSMA7 PET for primary N-staging of prostate cancer compared with histopathological findings.METHODS:Data from 58 consecutive patients with high risk prostate cancer (defined by D'Amico) who were staged with 18F-rhPSMA7 PET/CT or PET/MRI between July 2017 and June 2018 were reviewed. All patients underwent subsequent radical prostatectomy and extended pelvic lymph node dissection. An experienced read...

Upcoming role of prostate specific membrane antigen positron emission tomography-computed tomography in detecting occult metastases in prostate cancer

Prostate cancer (PCa) is the second most frequent malignancy in men. Most common sites of disease involvement other than the prostate gland include abdominopelvic lymph nodes and the skeleton. The detection of nodal metastases is of utmost importance to determine prognosis and choice of treatment in patients with PCa. Conventional imaging focuses on morphologic information and takes size criteria for decision-making. Early detection of metastases is further relevant in terms of prognosis and therapy management. Molecular imaging of PCa with Ga-68 prostate-specific membrane antigen (PSMA) positron emission tomography–computed tomography (PET-CT) has recently received significant attention and frequently used with a signature to PCa-specific remark. We presented the case of a 69-year-old male presenting with biochemical recurrence after undergoing surgery and in remission for about a year, where Ga-68 PSMA PET-CT identified additional sites of disease apart from the expected regional bed.

Primary Metastasis Staging Using&nbsp;18F-PSMA-1007 PET-CT in High-Risk Prostate Cancer: A Prospective Comparative Study of Advanced and Traditional Imaging Modalities

Background: Computed tomography (CT) and bone scintigraphy are the imaging modalities currently used for primary metastasis staging of high-risk prostate cancer (PCa). This trial compared these standard staging modalities with potentially more accurate imaging modalities: single photon emission computed tomography-CT (SPECT-CT), magnetic resonance imaging (MRI), prostate specific membrane antigen positron emission tomography (PSMA PET). Methods: This prospective, registered, single-centre, open-label, single-arm trial enrolled patients with primary high-risk PCa. Results of bone scintigraphy and CT were compared with 99mTc-HMDP SPECT-CT, 1.5T whole-body MRI using diffusion-weighted imaging and 18 F-PSMA-1007 PET-CT. Each imaging modality was reviewed by two independent experts blinded for the other modalities. The lesions were classified as benign, equivocal or malignant. Pessimistic and optimistic analyses were performed to resolve equivocal lesion status. Based on clinical data, including follow-up investigations, the best valuable comparator was defined at lesion level in multidisciplinary consensus meetings. Findings: 79 men were included and underwent all imaging modalities, except for one cancelled MRI due to claustrophobia. Mean age was 70 years and median PSA 12 ng/ml (range: 3-2000). Metastatic disease was detected in 27 (34%) patients. In pessimistic and optimistic analysis at patient, region and lesion levels, PSMA PET-CT was superior to all other modalities concerning sensitivity, and the area under curve values (AUC) at the bone region, while maintaining high specificity and demonstrating the highest inter-reader agreement. AUC for detection of bone metastasis for PSMA PET-CT was 0·94 (95%Cl;0·90-0·99) and 0·96 (95%CI;0·92-0·99) (reader 1, and reader 2, respectively) while AUC for all other modalities was in the range of 0·55-0·76. PSMA PET-CT revealed metastatic disease in 18/27 patients where standard imaging was negative. Interpretation: 18F-PSMA-1007 PET-CT outperformed other imaging methods in primary metastasis staging of high-risk PCa. We recommend further evaluation of this method as a new reference standard. Trial Registration number: (ClinicalTrials.gov NCT03537391). Funding Statement: This study was financially supported by grants from Finnish Government Research and Development Funds for Medical Research, Turku University Hospital and TYKS-SAPA Research Fund. Declaration of Interests: Dr. Anttinen reports grants from Profound Medical Inc, Finnish Urological Research Foundation and Finnish Urological Association, outside the submitted work. Dr. Ettala reports non-financial support from Ferring Pharmaceuticals Inc, SwanMedica and Pierre-Fabre Pharma Norden AB, and personal fees from Astellas, outside the submitted work. Dr. Sandell reports personal fees from Roche, outside the submitted work. Dr. Taimen reports personal fees from Roche, AstraZeneca and MSD, and non-financial support from MSD, all outside the submitted work. Dr. Bostrom reports grants from the Cancer Foundation Finland, personal fees from Profound Medical Inc and Janssen-Cilag Company, outside the submitted work. The other authors declare that there is no conflict of interest regarding the publication of this article. Ethical Approval Statement: The trial protocol, included in the Supplemental material, was approved by the ethics committee of the Hospital District of Southwest Finland, and written informed consent was obtained from all participants. The trial was performed in accordance with the principles of the Declaration of Helsinki.

Диагностические возможности ПЭТ/КТ 68GA-PSMA для пациентов с рецидивом рака предстательной железы

and aim. Most of the patients with biochemical recurrence after radical prostatectomy undergo salvage radiotherapy without guidance from imaging. In recent years, there has been an increasing role of Gallium-68 prostate specific membrane antigen (68Ga-PSMA) positron emission tomography/computed tomography (PET/CT) imaging in the management of prostate cancer. This study aimed to investigate diagnostic performance of 68Ga-PSMA PET/CT in patients with biochemical recurrence after radical prostatectomy. From 2016 to 2017, 19 prostate cancer patients were evaluated by 68Ga-PSMA PET/CT at the Urology Clinic of S.P Botkin City Clinical Hospital; 17 of them had a biochemical recurrence and needed restaging of the disease. The age, prostate specific antigen (PSA) values, therapy at the time of the study, and maximum standard uptake value (SUVmax) were evaluated. The median age of patients was 65 years (interquartile range (IQR) 58.5-70.5), the median total PSA level was 2.36 ng/mL (IQR 1.5-4.19). In 8 of 17 patients, the PSA values did not exceed 2 ng/ml. The median time after radical prostatectomy was 33.2 months. (IQR 12-54.5). Positive PET/CT sites of recurrence were detected in 15 of 17 patients. Nine patients had only one positive site, and in six patients several positive sites were detected. Four patients with PET/CT positive pelvic lymph nodes and/or retroperitoneal space underwent salvage lymphadenectomy. Histological findings confirmed the presence of malignant growth in 3 out of 4 cases. 68Ga-PSMA PET/CT is an effective tool for the early detection of oligometastatic lesions in recurrent prostate cancer.

PSMA-PET guided hook-wire localization of nodal metastases in prostate cancer: a targeted approach.

Prostate Specific Membrane Antigen Positron Emission Tomography/Computed Tomography (PSMA-PET/CT) has increased the sensitivity and specificity of imaging to identify metastatic prostate cancer in the group of patients with early biochemical recurrence when compared to conventional imaging. In patients who develop biochemical recurrence of prostate cancer following surgical resection, salvage lymph node dissection may reduce prostate specific antigen (PSA) levels and delay the time for commencement of systemic therapies. However, PLND may be an anatomically and technically difficult procedure, particularly with small metastatic diseases which can be problematic for intra-operative identification. We describe the technique using PSMA-PET imaging to pre-operatively localise areas of low-volume nodal metastatic disease with hookwire to allow targeted lymph node dissection with direct visualisation and palpation to ensure adequate clearance of involved nodes.

68Ga-PSMA Positron Emission Tomography/Computerized Tomography for Primary Diagnosis of Prostate Cancer in Men with Contraindications to or Negative Multiparametric Magnetic Resonance Imaging: A Prospective Observational Study

68Ga labeled prostate specific membrane antigen positron emission tomography/computerized tomography may represent the most promising imaging modality to identify and risk stratify prostate cancer in patients with contraindications to or negative multiparametric magnetic resonance imaging. In this prospective observational study we analyzed 68Ga labeled prostate specific membrane antigen positron emission tomography/computerized tomography in a select group of patients with persistently elevated prostate specific antigen and/or Prostate Health Index suspicious for prostate cancer, negative digital rectal examination and at least 1 negative biopsy. The cohort comprised men with equivocal multiparametric magnetic resonance imaging (Prostate Imaging-Reporting and Data System, version 2 score of 2 or less), or an absolute or relative contraindication to multiparametric magnetic resonance imaging. Sensitivity, specificity and CIs were calculated compared to histopathology findings. ROC analysis was applied to determine the optimal cutoff values of 68Ga labeled prostate specific membrane antigen uptake to identify clinically significant prostate cancer (Gleason score 7 or greater). A total of 45 patients with a median age of 64 years were referred for 68Ga labeled prostate specific membrane antigen positron emission tomography/computerized tomography between January and August 2017. The 25 patients (55.5%) considered to have positive positron emission tomography results underwent software assisted fusion biopsy. We determined the uptake values of regions of interest, including a median maximum standardized uptake value of 5.34 (range 2.25 to 30.41) and a maximum-to-background standardized uptake value ratio of 1.99 (range 1.06 to 14.42). Mean and median uptake values on 68Galabeled prostate specific membrane antigen positron emission tomography/computerized tomography (ie the maximum standardized uptake value or the maximum-to-background standardized uptake value ratio) were significantly higher for Gleason score 7 lesions than for Gleason score 6 or benign lesions (p <0.001). On ROC analysis a maximum standardized uptake value of 5.4 and a maximum-to-background standardized uptake value ratio of 2 discriminated clinically relevant prostate cancer with 100% overall sensitivity in each case, and 76% and 88% specificity, respectively. Our findings support the use of 68Ga labeled prostate specific membrane antigen positron emission tomography/computerized tomography for primary detection of prostate cancer in a specific subset of men.

68Ga-prostate specific membrane antigen (PSMA) positron emission tomography (PET) for primary staging of high-risk prostate cancer: a systematic review

To systematically review currently available data on 68Ga-prostate specific membrane antigen (PSMA) positron emission tomography (PET) used for the primary staging of high-risk prostate cancer. We performed critical reviews of EMBASE, Web of Science (including MEDLINE) and Cochrane databases in October 2016 according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. We included studies that utilized 68Ga-PSMA PET for primary staging of prostate cancer. Quality was assessed using the Critical Appraisal Skills Programme checklist for diagnostic test studies. Following our systematic search strategy, 12 studies were included for assessment. These studies comprised a total of 322 patients who underwent 68Ga-PSMA PET scanning for the purpose of primary staging. Only 5 of these studies included histopathologic correlation data. High variation in methodology and outcomes such as sensitivity (range 33-99%) and specificity (>90%) was seen across all studies. The ability of 68Ga-PSMA PET to detect malignant lesions was evident across studies, with most studies demonstrating increased detection rates with respect to conventional imaging modalities. In the primary staging of prostate cancer 68Ga-PSMA PET appears to outperform traditional imaging modalities. Overall, there are few high-quality studies investigating 68Ga-PSMA PET in this sub-group highlighting the need for formal assessment of PSMA PET in the form of large-volume, prospective studies.

A Comparative Study of 68Gallium-Prostate Specific Membrane Antigen Positron Emission Tomography-Computed Tomography and Magnetic Resonance Imaging for Lymph Node Staging in High Risk Prostate Cancer Patients: An Initial Experience.

Lymph node staging plays an important role in planning initial management in nonmetastatic prostate cancer. This article compares the role of 68Gallium (68Ga)-prostate specific membrane antigen (PSMA) positron emission tomography-computed tomography (PET-CT) with magnetic resonance imaging (MRI), which is considered the standard staging modality. Out of 39 high-risk prostate cancer patients who underwent 68Ga-PSMA PET-CT for staging (December 2014–December 2015), 12 patients underwent radical prostatectomy along with ePLND and were included in the analysis. Findings of the PSMA PET and MRI were compared with final histopathology. Sensitivity, specificity, positive predicative value (PPV), negative predicative value (NPV), and accuracy of 68Ga-PSMA PET-CT and MRI were calculated for numbers of patients and pelvic lymph node metastasis. Chi-square test, McNemar's test, and receiver operating characteristic (ROC) analysis were also done. 68Ga-PSMA PET-CT and MRI sensitivity, specificity, PPV, NPV, and accuracy for number of patients detection were 100%, 80%, 87.5%, 100%, 91.67%, and 57.14%, 80%, 80%, 57.4%, 66.67%, respectively. For detection of metastatic lymph node, it was 66.67%, 98.61%, 85.71%, 95.95%, 95.06% and 25.93%, 98.61%, 70%, 91.42%, 90.53%, respectively. Difference of lymph nodal detectability was statistically significant on Chi-square test. On McNemar's test, P value was statistically insignificant for number of patient detection (P = 0.250) but statistically significant for lymph nodal detection (P = 0.001) for 68Ga-PSMA PET-CT. In ROC analysis, area under the curve was also significantly high for lymph node detectability by 68Ga-PSMA PET-CT. Our initial experience shows that 68GaPSMA PET-CT is a very promising tracer for N staging in the initial workup of prostate cancer. It has the potential to impact patient's initial management and can up- and down-stage effectively.

68Ga-PSMA PET/CT for the detection of bone metastasis in recurrent prostate cancer and a PSA level

Localization of prostate cancer recurrence, particularly in the bones, is a major challenge with standard of care imaging in patients with biochemical recurrence following curatively intended treatment. Gallium-68-labeled prostate specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA PET/CT) is a novel and promising method for imaging in prostate cancer. The present study reports two cases of patients with prostate cancer with biochemical recurrence, with evidence of bone metastases on 68Ga-PSMA PET/CT images and low prostate specific antigen PSA levels (<2 ng/ml) and PSA doubling time >6 months. The bone metastases were verified by supplementary imaging with 18F-sodium fluoride PET/CT and magnetic resonance imaging as well as biochemical responses to androgen deprivation therapy. Therefore, 68Ga-PSMA PET/CT is promising for the restaging of patients with prostate cancer with biochemical recurrence, including patients with low PSA levels and low PSA kinetics.

Evaluation of the changing landscape of prostate cancer diagnosis and management from 2005 to 2016.

BackgroundApproaches to prostate cancer (PCa) diagnosis and treatment have evolved significantly over past decades. There has been an increasing focus on minimizing overdiagnosis and overtreatment of clinically insignificant PCa. The objective of this study was to evaluate the changes in the diagnostic approach and initial treatment strategy that has evolved over time in an Australian urological private practice.Materials and methodsMen with newly diagnosed PCa were identified from the private practice electronic and paper medical records from 2005 to 2016 and data was consolidated into six groups of 2-year intervals. Diagnostic strategy was analyzed with particular reference to the use of multiparametric magnetic resonance imaging (mpMRI) scan and 68Ga-prostate specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) scans. National Comprehensive Cancer Network risk group stratification was correlated with initial treatment strategy and compared over time.ResultsChart review identified 839 men who had a mean age of 65.8 years. In 2011–2012, prebiopsy mpMRI scan was introduced. Its uptake correlated with a decrease in numbers of men diagnosed with low risk cancer (r = -0.80, P = 0.04) and an increase in numbers of men diagnosed with high-risk cancer (r = 0.90, P = 0.01). The use of 68Ga-PSMA PET/CT was associated with decreasing use of CT and bone scans performed. Open radical prostatectomy had a declining trend particularly when robotic surgery (robotic assisted radical prostatectomy (RARP)) was introduced. Pelvic lymph node dissections performed progressively decreased. An increased use of luteinizing hormone receptor hormone (LHRH) antagonists was seen in favor of LHRH agonists. Whilst use of high dose rate brachytherapy declined, there was an increased use of low dose rate brachytherapy.ConclusionPrebiopsy mpMRI has been associated with an increased proportion of newly diagnosed men having clinically significant PCa. Over time, 68Ga-PSMA PET/CT scans, robotic assisted radical prostatectomy (RARP) and LHRH antagonists have increased in use, whilst CT and bone scans, and pelvic lymph node dissections have decreased.

Utility of 68 Ga prostate specific membrane antigen - positron emission tomography in diagnosis and response assessment of recurrent renal cell carcinoma.

Prostate specific membrane antigen (PSMA) positron emission tomography (PET) is an emerging imaging modality in prostate cancer. However, 68 Ga-PSMA-PET may also have diagnostic utility in the setting of renal cell carcinoma (RCC). We investigate the differential role of 18 F-fluorodeoxyglucose (FDG) and PSMA-PET/CT scanning in patients with oligometastatic RCC. In particular, we focus on the utility of PSMA-PET for diagnostic evaluation of isolated or limited metastases planned for local surgery or radiation, as well as the potential utility of PSMA-PET for therapeutic response assessment in patients receiving stereotactic ablative body radiotherapy (SABR). We present a retrospective series of eight patients in which comparative imaging modalities are evaluated against PSMA-PET scanning. FDG-PET and PSMA-PET scans were performed prior to definitive treatment (either surgery or SABR) of limited recurrent disease. Response assessment after SABR was performed with both PET imaging modalities at multiple time points in a subset of four patients. Prostate specific membrane antigen uptake is typically more intense than FDG in RCC. In all but two cases, one of which was papillary carcinoma, FDG-PET and PSMA-PET are concordant for detection of sites of disease. We demonstrate for the first time the differential kinetics of post-treatment response using PSMA and FDG-PET, with a more rapid metabolic response observed on FDG-PET. Both modalities demonstrate response earlier than morphological appearances on CT or MRI imaging. Our series suggests that PSMA shows early promise as a diagnostic and therapeutic response assessment tool in patients with metastatic RCC receiving definitive local therapies.

Information about Prostate Cancer for Urologist: Ga-68 Prostate Specific Membrane Antigen Positron Emission Tomography/Computed Tomography Scintigraphy

Information about Prostate Cancer for Urologist: Ga-68 Prostate Specific Membrane Antigen Positron Emission Tomography/Computed Tomography Scintigraphy

Prostate Specific Membrane Antigen Positron Emission Tomography May Improve the Diagnostic Accuracy of Multiparametric Magnetic Resonance Imaging in Localized Prostate Cancer

Positron emission tomography using ligands targeting prostate specific membrane antigen has recently been introduced. Positron emission tomography imaging with (68)Ga-PSMA-HBED-CC has been shown to detect metastatic prostate cancer lesions at a high rate. In this study we compare multiparametric magnetic resonance imaging and prostate specific membrane antigen positron emission tomography of the prostate with whole mount exvivo prostate histopathology to determine the true sensitivity and specificity of these imaging modalities for detecting and locating tumor foci within the prostate. In a prospective clinical trial setting 20 patients with localized prostate cancer and a planned radical prostatectomy were recruited. All patients underwent multiparametric magnetic resonance imaging and positron emission tomography before surgery, and whole mount histopathology slides were directly compared to the images. European Society of Urogenital Radiology guidelines for reporting magnetic resonance imaging were used as a template for regional units of analysis. The uropathologist and radiologists were blinded to individual components of the study, and the final correlation was performed by visual and deformable registration analysis. A total of 50 clinically significant lesions were identified from the whole mount histopathological analysis. Based on regional analysis the sensitivity, specificity, positive predictive value and negative predictive value for multiparametric magnetic resonance imaging were 44%, 94%, 81% and 76%, respectively. With prostate specific membrane antigen positron emission tomography the sensitivity, specificity, positive predictive value and negative predictive value were 49%, 95%, 85% and 88%, respectively. Prostate specific membrane antigen positron emission tomography yielded a higher specificity and positive predictive value. A significant proportion of cancers are potentially missed and underestimated by both imaging modalities. Prostate specific membrane antigen positron emission tomography may be used in addition to multiparametric magnetic resonance imaging to help improve local staging in those patients undergoing retropubic radical prostatectomy.

A Prospective Pilot Study of 89Zr-J591/Prostate Specific Membrane Antigen Positron Emission Tomography in Men with Localized Prostate Cancer Undergoing Radical Prostatectomy

In this pilot study we explored the feasibility of (89)Zr labeled J591 monoclonal antibody positron emission tomography of localized prostate cancer. Before scheduled radical prostatectomy 11 patients were injected intravenously with (89)Zr-J591, followed 6 days later by whole body positron emission tomography. Patients underwent surgery the day after imaging. Specimens were imaged by ex vivo micro positron emission tomography and a custom 3 Tesla magnetic resonance scanner coil. Positron emission tomography images and histopathology were correlated. Median patient age was 61 years (range 47 to 68), median prostate specific antigen was 5.2 ng/ml (range 3.5 to 12.0) and median biopsy Gleason score of the 11 index lesions was 7 (range 7 to 9). On histopathology 22 lesions were identified. Median lesion size was 5.5 mm (range 2 to 21) and median Gleason score after radical prostatectomy was 7 (range 6 to 9). Eight of 11 index lesions (72.7%) were identified by in vivo positron emission tomography. Lesion identification improved with increasing lesion size for in vivo and ex vivo positron emission tomography (each p <0.0001), and increasing Gleason score (p = 0.14 and 0.01, respectively). Standardized uptake values appeared to correlate with increased Gleason score but not significantly (p = 0.19). To our knowledge this is the first report of (89)Zr-J591/prostate specific membrane antigen positron emission tomography in localized prostate cancer cases. In this setting (89)Zr-J591 bound to tumor foci in situ and positron emission tomography identified primarily Gleason score 7 or greater and larger tumors, likely corresponding to clinically significant disease warranting definitive therapy. A future, larger clinical validation trial is planned to better define the usefulness of (89)Zr-J591 positron emission tomography for localized prostate cancer.

Characterizing Clinically Significant Prostate Cancer Using Template Prostate Mapping Biopsy

Definitions of prostate cancer risk are limited since accurate attribution of the cancer grade and burden is not possible due to the random and systematic errors associated with transrectal ultrasound guided biopsy. Transperineal prostate mapping biopsy may have a role in accurate risk stratification. We defined the transperineal prostate mapping biopsy characteristics of clinically significant disease. A 3-dimensional model of each gland and individual cancer was reconstructed using 107 radical whole mount specimens. We performed 500 transperineal prostate mapping simulations per case by varying needle targeting errors to calculate sensitivity, specificity, and negative and positive predictive value to detect lesions 0.2 ml or greater, or 0.5 ml or greater. Definitions of clinically significant cancer based on a combination of Gleason grade and cancer burden (cancer core length) were derived. Mean±SD patient age was 61±6.4 years (range 44 to 74) and mean prostate specific antigen was 9.7±5.9 ng/ml (range 0.8 to 36.2). We reconstructed 665 foci. The total cancer core length from all positive biopsies for a particular lesion that detected more than 95% of lesions 0.5 ml or greater and 0.2 ml or greater was 10 mm or greater and 6 mm or greater, respectively. The maximum cancer core length that detected more than 95% of lesions 0.5 ml or greater and 0.2 ml or greater was 6 mm or greater and 4 mm or greater, respectively. We combined these cancer burden thresholds with dominant and nondominant Gleason pattern 4 to derive 2 definitions of clinically significant disease. Transperineal prostate mapping may provide an effective method to risk stratify men with localized prostate cancer. The definitions that we present require prospective validation.