PROMIS is funded by the UK Government Department of Health, National Institute of Health Research-Health Technology Assessment Programme, (Project number 09/22/67). This project is also supported and partly funded by UCLH/UCL Biomedical Research Centre and The Royal Marsden and Institute for Cancer Research Biomedical Research Centre and is coordinated by the Medical Research Council Clinical Trials Unit (MRC CTU) at UCL. It is sponsored by University College London (UCL).

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in ; Vol. 22, No. 39. See the NIHR Journals Library website for further project information. This project was also supported and partially funded by the NIHR Biomedical Research Centre at University College London (UCL) Hospitals NHS Foundation Trust and UCL and by The Royal Marsden NHS Foundation Trust and The Institute of Cancer Research Biomedical Research Centre and was co-ordinated by the Medical Research Council's Clinical Trials Unit at UCL (grant code MC_UU_12023/28). It was sponsored by UCL. Funding for the additional collection of blood and urine samples for translational research was provided by Prostate Cancer UK.

BackgroundTransrectal ultrasound-guided prostate biopsies are prone to detection errors. Multi-parametric MRI (MP-MRI) may improve the diagnostic pathway.MethodsPROMIS is a prospective validating paired-cohort study that meets criteria for level 1 evidence in diagnostic test evaluation. PROMIS will investigate whether multi-parametric (MP)-MRI can discriminate between men with and without clinically-significant prostate cancer who are at risk prior to first biopsy. Up to 714 men will have MP-MRI (index), 10–12 core TRUS-biopsy (standard) and 5 mm transperineal template mapping (TPM) biopsies (reference). The conduct and reporting of each test will be blinded to the others.ResultsPROMIS will measure and compare sensitivity, specificity, and positive and negative predictive values of both MP-MRI and TRUS-biopsy against TPM biopsies. The MP-MRI results will be used to determine the proportion of men who could safely avoid biopsy without compromising detection of clinically-significant cancers. For the primary outcome, significant cancer on TPM is defined as Gleason grade >/= 4 + 3 and/or maximum cancer core length of ≥ 6 mm. PROMIS will also assess inter-observer variability among radiologists among other secondary outcomes. Cost-effectiveness of MP-MRI prior to biopsy will also be evaluated.ConclusionsPROMIS will determine whether MP-MRI of the prostate prior to first biopsy improves the detection accuracy of clinically-significant cancer.

Background All risk stratification strategies in cancer overlook a spectrum of disease. The Prostate MR Imaging Study (PROMIS) provides a unique opportunity to explore cancers that are overlooked by multiparametric magnetic resonance imaging (mpMRI). Objective To summarise attributes of cancers that are systematically overlooked by mpMRI. Design, setting, and participants PROMIS tested performance of mpMRI and transrectal ultrasonography (TRUS)-guided biopsy, using 5 mm template mapping (TPM) biopsy as the reference standard. Outcome measurements and statistical analysis Outcomes were overall and maximum Gleason scores, maximum cancer core length (MCCL), and prostate-specific antigen density (PSAD). Cancer attributes were compared between cancers that were overlooked and those that were detected. Results and limitations Of men with cancer, 7% (17/230; 95% confidence interval [CI] 4.4–12%) had significant disease overlooked by mpMRI according to definition 1 (Gleason ≥ 4 + 3 of any length or MCCL ≥ 6 mm of any grade) and 13% (44/331; 95% CI 9.8–17%) according to definition 2 (Gleason ≥ 3 + 4 of any length or MCCL ≥ 4 mm). In comparison, TRUS-guided biopsy overlooked 52% (119/230; 95% CI 45–58%) of significant disease by definition 1 and 40% (132/331; 95% CI 35–45%) by definition 2. Prostate cancers undetected by mpMRI had significantly lower overall and maximum Gleason scores ( p = 0.0007; p < 0.0001) and shorter MCCL (median difference: 3 mm [5 vs 8 mm], p < 0.0001; 95% CI 1–3) than cancers that were detected. No tumours with overall Gleason score > 3 + 4 (Gleason Grade Groups 3–5; 95% CI 0–6.4%) or maximum Gleason score > 4 + 3 (Gleason Grade Groups 4–5; 95% CI 0–8.0%) on TPM biopsy were undetected by mpMRI. Application of a PSAD threshold of 0.15 reduced the proportion of men with undetected cancer to 5% (12/230; 95% CI 2.7–8.9%) for definition 1 and 9% (30/331; 95% CI 6.2–13%) for definition 2. Application of a PSAD threshold of 0.10 reduced the proportion of men with undetected disease to 3% (6/230; 95% CI 1.0–5.6%) for definition 1 cancer and to 3% (11/331; 95% CI 1.7–5.9%) for definition 2 cancer. Limitations were post hoc analysis and uncertain significance of undetected lesions. Conclusions Overall, a small proportion of cancers are overlooked by mpMRI, with estimates ranging from 4.4% (lower boundary of 95% CI for definition 1) to 17% (upper boundary of 95% CI for definition 2). Prostate cancers undetected by mpMRI are of lower grade and shorter length than cancers that are detected. Patient summary Prostate cancers that are undetected by magnetic resonance imaging (MRI) are smaller and less aggressive than those that are detected, and none of the most aggressive cancers are overlooked by MRI.

Background False positive multiparametric magnetic resonance imaging (mpMRI) phenotypes prompt unnecessary biopsies. The Prostate MRI Imaging Study (PROMIS) provides a unique opportunity to explore such phenotypes in biopsy-naïve men with raised prostate-specific antigen (PSA) and suspected cancer. Objective To compare mpMRI lesions in men with/without significant cancer on transperineal mapping biopsy (TPM). Design, setting, and participants PROMIS participants ( n = 235) underwent mpMRI followed by a combined biopsy procedure at University College London Hospital, including 5-mm TPM as the reference standard. Patients were divided into four mutually exclusive groups according to TPM findings: (1) no cancer, (2) insignificant cancer, (3) definition 2 significant cancer (Gleason ≥3 + 4 of any length and/or maximum cancer core length ≥4 mm of any grade), and (4) definition 1 significant cancer (Gleason ≥4 + 3 of any length and/or maximum cancer core length ≥6 mm of any grade). Outcome measurements and statistical analysis Index and/or additional lesions present in 178 participants were compared between TPM groups in terms of number, conspicuity, volume, location, and radiological characteristics. Results and limitations Most lesions were located in the peripheral zone. More men with significant cancer had two or more lesions than those without significant disease (67% vs 37%; p <  0.001). In the former group, index lesions were larger (mean volume 0.68 vs 0.50 ml; p <  0.001, Wilcoxon test), more conspicuous (Likert 4–5: 79% vs 22%; p <  0.001), and diffusion restricted (mean apparent diffusion coefficient [ADC]: 0.73 vs 0.86; p <  0.001, Wilcoxon test). In men with Likert 3 index lesions, log 2 PSA density and index lesion ADC were significant predictors of definition 1/2 disease in a logistic regression model (mean cross-validated area under the receiver-operator characteristic curve: 0.77 [95% confidence interval: 0.67–0.87]). Conclusions Significant cancer-associated MRI lesions in biopsy-naïve men have clinical-radiological differences, with lesions seen in prostates without significant disease. MRI-calculated PSA density and ADC could predict significant cancer in those with indeterminate MRI phenotypes. Patient summary Magnetic resonance imaging (MRI) lesions that mimic prostate cancer but are, in fact, benign prompt unnecessary biopsies in thousands of men with raised prostate-specific antigen. In this study we found that, on closer look, such false positive lesions have different features from cancerous ones. This means that doctors could potentially develop better tools to identify cancer on MRI and spare some patients from unnecessary biopsies.

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In 41 months, 740 men at 11 centres were recruited; 576 underwent all three tests. Of 150 with MRI score 1-2, 8 (5.1%) had any Gleason >/=3+4 disease on TRUS-biopsy. In 75 where TRUS-biopsy showed Gleason 3+3 of any MCCL, 61/75 (81%) had Gleason 3+4, 8/75 (11%) Gleason 4+3 and 0/75 (0%) Gleason >/=4+5. For definition1 csPCa, TRUS-biopsy sensitivity remained stable and low across MP-MRI Likert scores (35%-52%). For definition2 csPCa and any cancer, sensitivity increased with higher MP-MRI score. Negative predictive value varied due to varying disease prevalence but for all cancer thresholds declined with increasing MP-MRI score. ConclusionsTRUS-biopsy in the setting of MP-MRI Likert scores 1-2 finds Gleason 3+4 disease in only 1 in 20 men. Further, for any csPCa definition, TRUS-biopsy had poor sensitivity and variable but low NPV across MP-MRI scores. Men undergoing TRUS-biopsy without targeting in the setting of MP-MRI score 3 to 5 should be advised to undergo a repeat (targeted) biopsy.

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