The Additive Diagnostic Value of Prostate-specific Membrane Antigen Positron Emission Tomography Computed Tomography to Multiparametric Magnetic Resonance Imaging Triage in the Diagnosis of Prostate Cancer (PRIMARY): A Prospective Multicentre Study.

BACKGROUND: Multiparametric magnetic resonance imaging (MRI) is validated for the detection of clinically significant prostate cancer (csPCa), although patients with negative/equivocal MRI undergo biopsy for false negative concerns. In addition, 68Ga-PSMA-11 positron emission tomography/computed tomography (prostate-specific membrane antigen [PSMA]) may also identify csPCa accurately. OBJECTIVE: This trial aimed to determine whether the combination of PSMA + MRI was superior to MRI in diagnostic performance for detecting csPCa. DESIGN, SETTING, AND PARTICIPANTS: A prospective multicentre phase II imaging trial was conducted. A total of 296 men were enrolled with suspected prostate cancer, with no prior biopsy or MRI, recent MRI (6 mo), and planned transperineal biopsy based on clinical risk and MRI. In all, 291 men underwent MRI, pelvic-only PSMA, and systematic ± targeted biopsy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Sensitivity, specificity, and predictive values (negative predictive value [NPV] and positive predictive value) for csPCa were determined for MRI, PSMA, and PSMA + MRI. PSMA + MRI was defined as negative for PSMA negative Prostate Imaging Reporting and Data System (PI-RADS) 2/3 and positive for either MRI PI-RADS 4/5 or PSMA positive PI-RADS 2/3; csPCa was any International Society of Urological Pathology (ISUP) grade group ≥2 malignancy. RESULTS AND LIMITATIONS: Of the patients, 56% (n = 162) had csPCa; 67% had PI-RADS 3-5, 73% were PSMA positive, and 81% were combined PSMA + MRI positive. Combined PSMA + MRI improved NPV compared with MRI alone (91% vs 72%, test ratio = 1.27 [1.11-1.39], p < 0.001). Sensitivity also improved (97% vs 83%, p < 0.001); however, specificity was reduced (40% vs 53%, p = 0.011). Five csPCa cases were missed with PSMA + MRI (four ISUP 2 and one ISUP 3). Of all men, 19% (56/291) were PSMA + MRI negative (38% of PI-RADS 2/3) and could potentially have avoided biopsy, risking delayed csPCa detection in 3.1% men with csPCa (5/162) or 1.7% (5/291) overall. CONCLUSIONS: PSMA + MRI improved NPV and sensitivity for csPCa in an MRI triaged population. Further randomised studies will determine whether biopsy can safely be omitted in men with a high clinical suspicion of csPCa but negative combined imaging. PATIENT SUMMARY: The combination of magnetic resonance imaging (MRI) + prostate-specific membrane antigen positron emission tomography reduces false negatives for clinically significant prostate cancer (csPCa) compared with MRI, potentially allowing a reduction in the number of prostate biopsies required to diagnose csPCa.

Diagnostic accuracy of 68 Ga-prostate-specific membrane antigen (PSMA) positron-emission tomography (PET) and multiparametric (mp)MRI to detect intermediate-grade intra-prostatic prostate cancer using whole-mount pathology: impact of the addition of 68 Ga-PSMA PET to mpMRI.

OBJECTIVE: To evaluate the ability of prostate-specific membrane antigen (PSMA)-positron-emission tomography (PET)/computed tomography (CT) to detect intermediate-grade intra-prostatic prostate cancer (PCa), and to determine if PSMA-PET improves the diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI). PATIENTS AND METHODS: A total of 56 consecutive patients with International Society of Urological Pathology (ISUP) grade 2-3 PCa after radical prostatectomy, who underwent both mpMRI and PSMA-PET CT (hereafter PSMA-PET) preoperatively, were enrolled in this study. The accuracy of PSMA-PET, mpMRI alone, and the two procedures in combination was analysed for identifying ISUP grades 1-3 within a 12-segment model. The accuracy of a combined predictive model (PSMA-PET and mpMRI) was determined. Receiver-operating characteristic curve analysis to determine the optimal standardized uptake value (SUVmax ) for PSMA-PET in discriminating between ISUP grades 1 and ≥2 was performed. RESULTS: On a per-patient basis, the sensitivities for PSMA-PET and mpMRI in identifying ISUP grades 2-3 PCa were 100% and 97%, respectively. Assessing ISUP grade ≥2 PCa using a 12-segment analysis, PSMA-PET demonstrated greater diagnostic accuracy (area under the curve), sensitivity, specificity, negative predictive value (NPV) and positive predictive value (PPV), with values of 0.91, 88%, 93%, 95% and 85%, respectively, than did mpMRI (Prostate Imaging Reporting and Data System [PI-RADS] 3-5), at 0.79, 68%, 91%, 87%, and 75%, respectively. When used in combination (PSMA-PET and mpMRI PIRADS 4-5), sensitivity, specificity, NPV and PPV were 92%, 90%, 96% and 81%, respectively. The sensitivity for both techniques reduced markedly when assessing ISUP grade 1 PCa (18% for PSMA-PET, 10% for mpMRI). An SUVmax value of 3.95 resulted in 94% sensitivity and 100% specificity. CONCLUSION: PSMA-PET is accurate in detecting segments containing intermediate-grade intra-prostatic PCa (ISUP grade ≥ 2), compared with and complementary to mpMRI. By contrast the detection rate for ISUP grade 1 disease for both PSMA-PET and mpMRI was low.

Aberrant neuropeptide Y and macrophage inhibitory cytokine-1 expression are early events in prostate cancer development and are associated with poor prognosis.

Studies to elucidate dysregulated gene expression patterns in premalignant prostate lesions have identified several candidate genes with the potential to be targeted to prevent the development and progression of prostate cancer and act as biomarkers of early disease. Herein, we explored the importance of two proteins, neuropeptide Y (NPY) and macrophage inhibitory cytokine-1 (MIC-1), as biomarkers of preinvasive prostate disease and investigated the relationship of expression to biochemical recurrence following treatment for localized prostate cancer. NPY and MIC-1 protein expression was determined by immunohistochemistry on tissue microarrays containing 1,626 cores of benign, low-grade prostatic intraepithelial neoplasia (PIN), high-grade PIN (HGPIN), and prostate cancer tissue from 243 radical prostatectomy patients. Both NPY and MIC-1 showed higher proportional immunostaining in HGPIN and prostate cancer compared with benign epithelium (P < 0.0001). NPY and MIC-1 immunostaining was higher in low-grade PIN compared with other benign tissues (both P < 0.0001) and was equivalent to immunostaining in HGPIN. NPY immunostaining of prostate cancer was independently associated with relapse, after adjusting for traditional prognostic factors, as a categorical variable in 20% intervals (P = 0.0449-0.0103) and as a continuous variable (P = 0.0017). Low MIC-1 immunostaining (20% categories) was associated with pathologic stage >2C after adjusting for predictors of pathologic stage (P = 0.3894-0.0176). This is the first study to show that altered NPY and MIC-1 expression are significantly associated with prostate cancer progression and suggests that these molecules be developed further as biomarkers in the management of prostate disease.

Lower levels of nuclear beta-catenin predict for a poorer prognosis in localized prostate cancer.

Beta-catenin in its role as a nuclear signaling molecule has been implicated in prostate carcinogenesis primarily through modulation of androgen receptor activity. We defined the pattern of beta-catenin protein expression in the nuclei of normal, hyperplastic and malignant human prostate tissue and determined whether differences in expression were associated with disease progression and prognosis. Five normal prostates, 26 benign prostatic hypertrophy specimens, 232 radical prostatectomy specimens from patients with clinically localized prostate cancer (PC) and 20 cases of advanced PC were assessed for beta-catenin expression using immunohistochemistry. Nuclear beta-catenin expression in localized PC was significantly lower than that in benign prostate tissue (p < 0.001) and significantly higher than that in advanced PC tissue (p < 0.001). In addition, lower levels of nuclear beta-catenin expression (< 10% of cancer cells) predicted for a shorter biochemical relapse-free survival in patients with localized PC (p = 0.008) and were inversely correlated with preoperative prostate-specific antigen (PSA) levels (p = 0.01). Analysis of the low-risk subgroup of patients with preoperative PSA levels < 10 ng/ml demonstrated that lower levels of nuclear beta-catenin expression (< 10% of cancer cells) again predicted for a poorer prognosis (p = 0.006). In conclusion, lower levels of nuclear beta-catenin expression are found in malignant compared to benign prostate tissue. In addition, lower nuclear beta-catenin expression is associated with a poorer prognosis in localized PC, in particular, in the low-risk subgroup of patients with preoperative PSA levels < 10 ng/ml. Thus, the level of nuclear beta-catenin expression may be of clinical utility as a preoperative prognostic marker in low-risk localized PC.

Loss of BMP2, Smad8, and Smad4 expression in prostate cancer progression.

BACKGROUND: The role of the bone morphogenetic protein (BMP) pathway in prostate cancer (PC) is unclear. This study aimed to characterize aspects of the BMP pathway in PC by assessing BMP2, Smad8, and Smad4 expression in normal, hyperplastic, and malignant prostate tissue, and to correlate findings with progression to PC. METHODS: Radical prostatectomy (RP) specimens from 74 patients with clinically localized PC (median follow-up 51 months, range 15-152), 44 benign prostatic hypertrophy (BPH) lesions, and 4 normal prostates (NPs) were assessed for BMP2, Smad8, and Smad4 expression using immunohistochemistry. RESULTS: Both BMP2 (P < 0.001) and nuclear Smad4 (P < 0.0001) expression were significantly decreased in PC compared to benign prostate tissue. Nuclear Smad8 was present in normal/benign prostate tissue but absent in PC and adjacent hyperplasia. Furthermore, loss of BMP2 (P < 0.001) and decreased nuclear Smad4 (P = 0.05) expression correlated with increasing Gleason score. CONCLUSIONS: These data suggest that decreased BMP2, nuclear smad8 and nuclear Smad4 expression are associated with the progression to PC, and in particular loss of BMP2 and Smad4 are related to progression to a more aggressive phenotype.

Membranous expression of secreted frizzled-related protein 4 predicts for good prognosis in localized prostate cancer and inhibits PC3 cellular proliferation in vitro.

PURPOSE: Activation of the Wnt-signaling pathway is implicated in aberrant cellular proliferation in a variety of cancers. Secreted frizzled-related protein 4 (sFRP4) is a secreted protein with putative inhibitory activity of the Wnt-signaling cascade through binding and sequestering Wnt ligands. Because sFRP4 mRNA is overexpressed in prostate cancers (PCs), the aim of this study was to define the pattern of sFRP4 protein expression in normal and malignant human prostate tissue and to determine whether changes in expression were associated with disease progression and prognosis, as well as to define the phenotype of sFRP4-overexpression in an in vitro model of PC. EXPERIMENTAL DESIGN: Polyclonal antibodies were raised against a COOH-terminal peptide of sFRP4, characterized and used to assess sFRP4 protein expression in benign prostate tissue and 229 patients with clinically localized PC (median follow-up 77 months, range 1-156). In vitro studies of the function of sFRP4 overexpression were performed using PC3 cells transfected with sFRP4. RESULTS: Benign and malignant prostate tissue demonstrated cytoplasmic sFRP4 immunoreactivity, but there was a decrease in the expression of membranous sFRP4 in PCs compared with the hyperplastic lesions (P < 0.0001). Kaplan-Meier analysis revealed that patients whose PC expressed membranous sFRP4 in >20% of cells had improved relapse-free survival compared with those with

Prognostic significance of Gleason pattern in patients with Gleason score 7 prostate carcinoma.

BACKGROUND: In the current study, the authors sought to further stratify the prognosis of patients with Gleason score (GS) 7 prostate carcinoma. They assessed the influence on outcome of a predominant poorly differentiated Gleason pattern (primary Gleason pattern [GP] 4) and/or a coincident small focus of poorly differentiated tumor of higher grade (tertiary GP 5). METHODS: The authors studied 412 patients (mean postoperative follow-up, 33 months) with GS 7 tumors treated with radical prostatectomy at a single Australian campus between November 1989 and December 2002. The chi-square test, Kaplan-Meier method, and Cox proportional hazards analyses were used to evaluate the correlation between primary GP 4 and tertiary GP 5 with the occurrence of adverse pathologic features and disease recurrence. RESULTS: In this cohort, 307 patients (75%) had primary GP 3 tumors, 105 (25%) had primary GP 4 tumors, and 17 (2.3%) had a tertiary element of high-grade tumor (GP 5). Patients with primary GP 4 tumors displayed higher rates of seminal vesicle involvement and extraprostatic extension and, along with patients with tertiary GP 5, had significantly shorter times to disease recurrence. Univariate analysis demonstrated that primary GP 4 (P = 0.0003) and tertiary GP 5 (P < 0.0001) were strong predictors of disease recurrence. Primary GP 4 (P = 0.0122) remained an independent predictor of disease recurrence on stepwise multivariate analysis. CONCLUSIONS: Primary GP 4 tumors represented an aggressive subset of GS 7 prostate carcinomas. Primary GP was an easily accessible and clinically relevant predictor of disease recurrence in patients with GS 7 prostate carcinoma.

Expression of the zinc transporter ZnT4 is decreased in the progression from early prostate disease to invasive prostate cancer.

We have utilized oligonucleotide microarrays to identify novel genes of potential clinical and biological importance in prostate cancer. RNA from 74 prostate cancers and 164 normal body samples representing 40 different tissues were analysed using a customized Affymetrix GeneChip oligonucleotide microarray representative of over 90% of the expressed human genome. The gene for the zinc transporter ZnT4 was one of several genes that displayed significantly higher expression in prostate cancer compared to normal tissues from other organs. A polyclonal antipeptide antibody was used to demonstrate ZnT4 expression in the epithelium of all 165 elements of benign and 326 elements of localized prostate cancers examined and in nine of 10 advanced prostate cancer specimens by immunohistochemistry. Interestingly, decreased intensity of ZnT4 immunoreactivity occurred in the progression from benign to invasive localized prostate cancer and to metastatic disease. Immunofluorescence analysis and surface biotinylation studies of cells expressing ZnT4 localised the protein to intracellular vesicles and to the plasma membrane. These findings are consistent with a role for ZnT4 in vesicular transport of zinc to the cell membrane and potentially in efflux of zinc in the prostate.

Prognostic significance of preoperative factors in localized prostate carcinoma treated with radical prostatectomy: importance of percentage of biopsies that contain tumor and the presence of biopsy perineural invasion.

BACKGROUND: Predicting outcome for men with clinically localized prostate carcinoma treated with curative intent remains imprecise and further evaluation of accepted and potential predictive factors is needed. METHODS: The authors studied 696 men with localized prostate carcinoma diagnosed on transrectal biopsy and treated with radical prostatectomy at one institution between 1986 and 1999 to determine the relation between putative pretreatment prognostic factors and disease-free survival. Clinical stage, Gleason score, perineural invasion, number of biopsies containing tumor, and serum prostate specific antigen (PSA) were evaluated as predictors of extracapsular extension, seminal vesicle involvement, lymph node metastases, and surgical margin involvement as well as outcome after surgery. Kaplan-Meier method and Cox regression analyses were used to evaluate the contribution of different factors to adverse pathologic features and relapse. RESULTS: At mean follow-up of 56.9 months (range, 1.0-177.9 months; median, 54.9 months), 26.1% (182 of 696 patients) of patients had developed a disease recurrence. Pretreatment serum PSA concentration, biopsy Gleason score, and clinical stage as well as number of biopsies involved with tumor as a percentage of the total number obtained were found to be independent predictors of outcome. In patients with PSA > 10 ng/mL, biopsy perineural invasion and percentage of biopsies containing tumor were found to independently predicted disease recurrent. Increased number of biopsies involved with tumor independently predicted extracapsular extension, margin involvement, seminal vesicle, and lymph node involvement. CONCLUSIONS: This study demonstrated that the proportion of prostate biopsy cores containing tumor is an independent predictor of outcome after subsequent radical prostatectomy and suggested that perineural invasion has a predictive role in patients with a preoperative PSA > 10 ng/ml.