The PICTURE study: diagnostic accuracy of multiparametric MRI in men requiring a repeat prostate biopsy.

BACKGROUND: Transrectal prostate biopsy has limited diagnostic accuracy. Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE) was a paired-cohort confirmatory study designed to assess diagnostic accuracy of multiparametric magnetic resonance imaging (mpMRI) in men requiring a repeat biopsy. METHODS: All underwent 3 T mpMRI and transperineal template prostate mapping biopsies (TTPM biopsies). Multiparametric MRI was reported using Likert scores and radiologists were blinded to initial biopsies. Men were blinded to mpMRI results. Clinically significant prostate cancer was defined as Gleason ⩾4+3 and/or cancer core length ⩾6 mm. RESULTS: Two hundred and forty-nine had both tests with mean (s.d.) age was 62 (7) years, median (IQR) PSA 6.8 ng ml (4.98-9.50), median (IQR) number of previous biopsies 1 (1-2) and mean (s.d.) gland size 37 ml (15.5). On TTPM biopsies, 103 (41%) had clinically significant prostate cancer. Two hundred and fourteen (86%) had a positive prostate mpMRI using Likert score ⩾3; sensitivity was 97.1% (95% confidence interval (CI): 92-99), specificity 21.9% (15.5-29.5), negative predictive value (NPV) 91.4% (76.9-98.1) and positive predictive value (PPV) 46.7% (35.2-47.8). One hundred and twenty-nine (51.8%) had a positive mpMRI using Likert score ⩾4; sensitivity was 80.6% (71.6-87.7), specificity 68.5% (60.3-75.9), NPV 83.3% (75.4-89.5) and PPV 64.3% (55.4-72.6). CONCLUSIONS: In men advised to have a repeat prostate biopsy, prostate mpMRI could be used to safely avoid a repeat biopsy with high sensitivity for clinically significant cancers. However, such a strategy can miss some significant cancers and overdiagnose insignificant cancers depending on the mpMRI score threshold used to define which men should be biopsied

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Understanding prostate cancer

Prostate cancer is the second most common cancer affecting men in Europe and the USA. The incidence of prostate cancer has risen by 60-75% in the Western world in the last 15 years. One in twelve men over the age of 60 develop prostate cancer and this figure is expected to rise to three in twelve in the next 20 years. Early prostate cancer often does not cause symptoms. However, patients may present with lower urinary tract symptoms (LUTS) and therefore, such patients should be investigated. Effective treatment in the form of surgery and radiotherapy is availabLe for individuals with localised disease, and the effectiveness of different combination therapy is being assessed to improve the outcome further. Approximately 20% of the patients have metastatic disease on presentation. The mainstay of treatment for these patients is androgen ablation therapy; however patients on this regime eventually relapse and develop an androgen independent tumour. This aggressive stage of the disease carries a high morbidity and mortality. At present the treatment for such hormone refractory prostate cancer is inadequate and the desperate search for alternative forms of therapy continues

Prostate Imaging Compared to Transperineal Ultrasound-guided biopsy for significant prostate cancer Risk Evaluation (PICTURE): a prospective cohort validating study assessing Prostate HistoScanning.

BACKGROUND: Men with negative prostate biopsies or those diagnosed with low-risk or low-volume intermediate-risk prostate cancers often require a second prostate biopsy prior to a treatment decision. Prostate HistoScanning (PHS) is an ultrasound imaging test that might inform prostate biopsy in such men. METHODS: PICTURE was a prospective, paired-cohort validating trial to assess the diagnostic accuracy of imaging in men requiring a further biopsy (clinicaltrials.gov, NCT01492270) (11 January 2012-29 January 2014). We enrolled 330 men who had undergone a prior TRUS biopsy but where diagnostic uncertainty remained. All eligible men underwent PHS and transperineal template prostate mapping (TTPM) biopsy (reference standard). Men were blinded to the imaging results until after undergoing TTPM biopsies. We primarily assessed the ability of PHS to rule out clinically significant prostate (negative predictive value [NPV] and sensitivity) for a target histological condition of Gleason ≥4+3 and/or a cancer core length (MCCL) ≥6 mm. We also assessed the role of visually estimated PHS-targeted biopsies. RESULTS: Of the 330 men enrolled, 249 underwent both PHS and TTPM biopsy. Mean (SD) age was 62 (7) years, median (IQR) PSA 6.8 (4.98-9.50) ng/ml, median (IQR) number of previous biopsies 1 (1-2) and mean (SD) gland size 37 (15.5) ml. One hundred and forty six (59%) had no clinically significant cancer. PHS classified 174 (70%) as suspicious. Sensitivity was 70.3% (95% CI 59.8-79.5) and NPV 41.3% (95% CI 27.0-56.8). Specificity and positive predictive value (PPV) were 14.7% (95% CI 9.1-22.0) and 36.8% (95% CI 29.6-44.4), respectively. In all, 213/220 had PHS suspicious areas targeted with targeting sensitivity 13.6% (95% CI 7.3-22.6), specificity 97.6% (95% CI 93.1-99.5), NPV 61.6% (95% CI 54.5-68.4) and PPV 80.0% (95% CI 51.9-95.7). CONCLUSIONS: PHS is not a useful test in men seeking risk stratification following initial prostate biopsy

Immunohistochemical biomarker validation in highly selective needle biopsy microarrays derived from mpMRI-characterized prostates.

INTRODUCTION: Diagnosing prostate cancer routinely involves tissue biopsy and increasingly image guided biopsy using multiparametric MRI (mpMRI). Excess tissue after diagnosis can be used for research to improve the diagnostic pathway and the vertical assembly of prostate needle biopsy cores into tissue microarrays (TMAs) allows the parallel immunohistochemical (IHC) validation of cancer biomarkers in routine diagnostic specimens. However, tissue within a biopsy core is often heterogeneous and cancer is not uniformly present, resulting in needle biopsy TMAs that suffer from highly variable cancer detection rates that complicate parallel biomarker validation. MATERIALS AND METHODS: The prostate cores with the highest tumor burden (in terms of Gleason score and/or maximum cancer core length) were obtained from 249 patients in the PICTURE trial who underwent transperineal template prostate mapping (TPM) biopsy at 5 mm intervals preceded by mpMRI. From each core, 2 mm segments containing tumor or benign tissue (as assessed on H&E pathology) were selected, excised and embedded vertically into a new TMA block. TMA sections were then IHC-stained for the routinely used prostate cancer biomarkers PSA, PSMA, AMACR, p63, and MSMB and assessed using the h-score method. H-scores in patient matched malignant and benign tissue were correlated with the Gleason grade of the original core and the MRI Likert score for the sampled prostate area. RESULTS: A total of 2240 TMA cores were stained and IHC h-scores were assigned to 1790. There was a statistically significant difference in h-scores between patient matched malignant and adjacent benign tissue that is independent of Likert score. There was no association between the h-scores and Gleason grade or Likert score within each of the benign or malignant groups. CONCLUSION: The construction of highly selective TMAs from prostate needle biopsy cores is possible. IHC data obtained through this method are highly reliable and can be correlated with imaging. IHC expression patterns for PSA, PSMA, AMACR, p63, and MSMB are distinct in malignant and adjacent benign tissue but did not correlate with mpMRI Likert score

Multiple loci on 8q24 associated with prostate cancer susceptibility

Previous studies have identified multiple loci on 8q24 associated with prostate cancer risk. We performed a comprehensive analysis of SNP associations across 8q24 by genotyping tag SNPs in 5,504 prostate cancer cases and 5,834 controls. We confirmed associations at three previously reported loci and identified additional loci in two other linkage disequilibrium blocks (rs1006908: per-allele OR = 0.87, P = 7.9 x 10(-8); rs620861: OR = 0.90, P = 4.8 x 10(-8)). Eight SNPs in five linkage disequilibrium blocks were independently associated with prostate cancer susceptibility

Identification of seven new prostate cancer susceptibility loci through a genome-wide association study

Prostate cancer (PrCa) is the most frequently diagnosed male cancer in developed countries. To identify common PrCa susceptibility alleles, we have previously conducted a genome-wide association study in which 541, 129 SNPs were genotyped in 1,854 PrCa cases with clinically detected disease and 1,894 controls. We have now evaluated promising associations in a second stage, in which we genotyped 43,671 SNPs in 3,650 PrCa cases and 3,940 controls, and a third stage, involving an additional 16,229 cases and 14,821 controls from 21 studies. In addition to previously identified loci, we identified a further seven new prostate cancer susceptibility loci on chromosomes 2, 4, 8, 11, and 22 (P=1.6×10−8 to P=2.7×10−33)