Diagnostic accuracy of multi-parametric MRI and TRUS biopsy in prostate cancer (PROMIS): a paired validating confirmatory study.

BACKGROUND: Men with high serum prostate specific antigen usually undergo transrectal ultrasound-guided prostate biopsy (TRUS-biopsy). TRUS-biopsy can cause side-effects including bleeding, pain, and infection. Multi-parametric magnetic resonance imaging (MP-MRI) used as a triage test might allow men to avoid unnecessary TRUS-biopsy and improve diagnostic accuracy. METHODS: We did this multicentre, paired-cohort, confirmatory study to test diagnostic accuracy of MP-MRI and TRUS-biopsy against a reference test (template prostate mapping biopsy [TPM-biopsy]). Men with prostate-specific antigen concentrations up to 15 ng/mL, with no previous biopsy, underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy. The conduct and reporting of each test was done blind to other test results. Clinically significant cancer was defined as Gleason score ≥4 + 3 or a maximum cancer core length 6 mm or longer. This study is registered on ClinicalTrials.gov, NCT01292291. FINDINGS: Between May 17, 2012, and November 9, 2015, we enrolled 740 men, 576 of whom underwent 1·5 Tesla MP-MRI followed by both TRUS-biopsy and TPM-biopsy. On TPM-biopsy, 408 (71%) of 576 men had cancer with 230 (40%) of 576 patients clinically significant. For clinically significant cancer, MP-MRI was more sensitive (93%, 95% CI 88-96%) than TRUS-biopsy (48%, 42-55%; p<0·0001) and less specific (41%, 36-46% for MP-MRI vs 96%, 94-98% for TRUS-biopsy; p<0·0001). 44 (5·9%) of 740 patients reported serious adverse events, including 8 cases of sepsis. INTERPRETATION: Using MP-MRI to triage men might allow 27% of patients avoid a primary biopsy and diagnosis of 5% fewer clinically insignificant cancers. If subsequent TRUS-biopsies were directed by MP-MRI findings, up to 18% more cases of clinically significant cancer might be detected compared with the standard pathway of TRUS-biopsy for all. MP-MRI, used as a triage test before first prostate biopsy, could reduce unnecessary biopsies by a quarter. MP-MRI can also reduce over-diagnosis of clinically insignificant prostate cancer and improve detection of clinically significant cancer. FUNDING: 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).

Prostate-specific antigen vs. magnetic resonance imaging parameters for assessing oncological outcomes after high intensity-focused ultrasound focal therapy for localized prostate cancer.

INTRODUCTION: Focal therapy for localized prostate cancer has the potential for oncological control without the side effects of radical therapies. However, there is currently no validated method for monitoring treatment success. We assessed the diagnostic performance of prostate-specific antigen (PSA) parameters and MRI compared to histological outcomes following focal therapy. PATIENTS AND METHODS: Patients from 3 Ethics Review Board approved prospective studies of focal high intensity-focused ultrasound (HIFU) (Sonablate 500) for localized prostate cancer (T1c-T3a, Gleason grade≤4+3, and PSA≤20). Post-HIFU PSA nadir, 6-month PSA, PSA density, and early (<3wk) and late (6mo) MRI (T2-weighted, dynamic contrast-enhanced±diffusion-weighted) was assessed for predictive accuracy of cancer on postoperative biopsy, using receiver operating characteristic (ROC) analysis and sensitivity, specificity, and positive and negative predictive estimates. ROC areas for MRI and PSA were compared. Calculations for statistical significance (P≤0.05) were obtained in a subset of patients comparing area under ROC for 6-month MRI and PSA criteria, across 4 different histological definitions of disease significance. RESULTS: Of 118 men, 111 underwent at least 1 postoperative biopsy (median 6 cores), with an overall positive biopsy rate of 37% (41/118), over a mean follow-up period of 716 days post-HIFU. Areas under ROC for early and late MRI were (depending on definition of significant disease) 0.65 to 0.76 and 0.77 to 0.85, respectively, with sensitivity, specificity, and negative predictive values of 68% to 91%, 52% to 55%, and 85% to 98% (early MRI), and 63% to 80%, 67% to 73%, and 86% to 97% (late MRI). The area under the ROC curve was statistically significantly higher for late MRI than 6 months and nadir PSA for residual disease >3mm or any Gleason 4 tumor. CONCLUSIONS: Early and late MRI performed better than PSA measurements in the detection of residual tumor after focal therapy.

Focal Ablation Targeted to the Index Lesion in Multifocal Localised Prostate Cancer: a Prospective Development Study.

BACKGROUND: Although localised prostate cancer is multifocal in most instances, the index lesion might be responsible for disease progression. OBJECTIVE: To determine the early genitourinary functional and cancer control outcomes of index lesion ablation. DESIGN, SETTING, AND PARTICIPANTS: This was a single-centre prospective development study in which 56 men were treated (July 2009-January 2011). The mean age was 63.9 yr (standard deviation 5.8) and median prostate-specific antigen (PSA) was 7.4 ng/ml (interquartile range [IQR] 5.6-9.5). There were seven (12.5%) low-risk, 47 (83.9%) intermediate-risk, and two (3.6%) high-risk cancers. INTERVENTION: Multiparametric magnetic resonance imaging (mpMRI) and prostate biopsies to localise disease, followed by index lesion ablation using high-intensity focused ultrasound. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Primary outcomes were genitourinary side effects measured using validated questionnaires. Secondary outcomes included absence of clinically significant disease at 12 mo. RESULTS AND LIMITATIONS: The composite of leak-free, pad-free continence, and erections sufficient for penetration decreased from a baseline frequency of 40/56 (71.4%) to 33/56 (58.9%) at 12 mo. Pad-free and leak-free, pad-free continence was preserved in 48/52 (92.3%) and 46/50 (92.0%) patients, respectively. Erections sufficient for intercourse were preserved in 30/39 (76.9%) patients. The median PSA nadir decreased to 2.4 ng/ml (IQR 1.6-4.1). At 12 mo, 42/52 (80.8%) patients had histological absence of clinically significant cancer and 85.7% (48/56) had no measurable prostate cancer (biopsy and/or mpMRI). Two (3.6%) patients had clinically significant disease in untreated areas not detected at baseline. The main study limitation is the short follow-up duration. CONCLUSIONS: Index lesion ablation had low rates of genitourinary side effects and acceptable short-term absence of clinically significant cancer. Comparative effectiveness trials are required to assess cancer control outcomes against radical therapy. PATIENT SUMMARY: In this study we looked at whether it is possible to treat the largest and highest-grade tumour in men who have more than one known prostate tumour. We show that the side effects of targeted ablation were low, with acceptable rates of early cancer control. Larger studies with longer follow-up are needed. TRIAL REGISTRATION: NCT00988130.

Image-directed, tissue-preserving focal therapy of prostate cancer: a feasibility study of a novel deformable magnetic resonance-ultrasound (MR-US) registration system.

OBJECTIVE: To evaluate the feasibility of using computer-assisted, deformable image registration software to enable three-dimensional (3D), multi-parametric (mp) magnetic resonance imaging (MRI)-derived information on tumour location and extent, to inform the planning and conduct of focal high-intensity focused ultrasound (HIFU) therapy. PATIENTS AND METHODS: A nested pilot study of 26 consecutive men with a visible discrete focus on mpMRI, correlating with positive histology on transperineal template mapping biopsy, who underwent focal HIFU (Sonablate 500®) within a prospective, Ethics Committee-approved multicentre trial ('INDEX'). Non-rigid image registration software developed in our institution was used to transfer data on the location and limits of the index lesion as defined by mpMRI. Manual contouring of the prostate capsule and histologically confirmed MR-visible lesion was performed preoperatively by a urologist and uro-radiologist. A deformable patient-specific computer model, which captures the location of the target lesion, was automatically generated for each patient and registered to a 3D transrectal ultrasonography (US) volume using a small number (10-20) of manually defined capsule points. During the focal HIFU, the urologist could add additional sonications after image-registration if it was felt that the original treatment plan did not cover the lesion sufficiently with a margin. RESULTS: Prostate capsule and lesion contouring was achieved in <5 min preoperatively. The mean (range) time taken to register images was 6 (3-16) min. Additional treatment sonications were added in 13 of 26 cases leading to a mean (range) additional treatment time of 45 (9-90) s. CONCLUSION: Non-rigid MR-US registration is feasible, efficient and can locate lesions on US. The process has potential for improved accuracy of focal treatments, and improved diagnostic sampling strategies for prostate cancer. Further work on whether deformable MR-US registration impacts on efficacy is required.

Scoring systems used for the interpretation and reporting of multiparametric MRI for prostate cancer detection, localization, and characterization: could standardization lead to improved utilization of imaging within the diagnostic pathway?

Multiparametric magnetic resonance imaging (mpMRI) is increasingly being used earlier in the prostate cancer diagnostic pathway in order to detect and localize disease. Its results can be used to help decide on the indication, type, and localization of a prostate biopsy for cancer diagnosis. In addition, mpMRI has the potential to contribute information on the characterization, or aggressiveness, of detected cancers including tumor progression over time. There is considerable variation in the way results of different MRI sequences are reported. We conducted a review of scoring systems that have been used in the detection and characterization of prostate cancer. This revealed that existing scoring and reporting systems differ in purpose, scale, and range. We evaluate these differences in this review. This first step in collating all methods of scoring and reporting mpMRI will ultimately lead to consensus approaches to develop a standardized reporting scheme that can be widely adopted and validated to ensure comparability of research outputs and optimal clinical practice.

Focal therapy for localised unifocal and multifocal prostate cancer: a prospective development study.

BACKGROUND: Radical whole-gland therapy can lead to significant genitourinary and rectal side-effects for men with localised prostate cancer. We report on whether selective focal ablation of unifocal and multifocal cancer lesions can reduce this treatment burden. METHODS: Men aged 45-80 years were eligible for this prospective development study if they had low-risk to high-risk localised prostate cancer (prostate specific antigen [PSA] ≤15 ng/mL, Gleason score ≤4 + 3, stage ≤T2), with no previous androgen deprivation or treatment for prostate cancer, and who could safely undergo multiparametric MRI and have a general anaesthetic. Patients received focal therapy using high-intensity focused ultrasound, delivered to all known cancer lesions, with a margin of normal tissue, identified on multiparametric MRI, template prostate-mapping biopsies, or both. Primary endpoints were adverse events (serious and otherwise) and urinary symptoms and erectile function assessed using patient questionnaires. Analyses were done on a per-protocol basis. This study is registered with ClinicalTrials.gov, number NCT00561314. FINDINGS: 42 men were recruited between June 27, 2007, and June 30, 2010; one man died from an unrelated cause (pneumonia) 3 months after treatment and was excluded from analyses. After treatment, one man was admitted to hospital for acute urinary retention, and another had stricture interventions requiring hospital admission. Nine men (22%, 95% CI 11-38) had self-resolving, mild to moderate, intermittent dysuria (median duration 5·0 days [IQR 2·5-18·5]). Urinary debris occurred in 14 men (34%, 95% CI 20-51), with a median duration of 14·5 days (IQR 6·0-16·5). Urinary tract infection was noted in seven men (17%, 95% CI 7-32). Median overall International Index of Erectile Function-15 (IIEF-15) scores were similar at baseline and at 12 months (p=0·060), as were median IIEF-15 scores for intercourse satisfaction (p=0·454), sexual desire (p=0·644), and overall satisfaction (p=0·257). Significant deteriorations between baseline and 12 months were noted for IIEF-15 erectile (p=0·042) and orgasmic function (p=0·003). Of 35 men with good baseline function, 31 (89%, 95% CI 73-97) had erections sufficient for penetration 12 months after focal therapy. Median UCLA Expanded Prostate Cancer Index Composite (EPIC) urinary incontinence scores were similar at baseline as and 12 months (p=0·045). There was an improvement in lower urinary tract symptoms, assessed by International Prostate Symptom Score (IPSS), between baseline and 12 months (p=0·026), but the IPSS-quality of life score showed no difference between baseline and 12 months (p=0·655). All 38 men with no baseline urinary incontinence were leak-free and pad-free by 9 months. All 40 men pad-free at baseline were pad-free by 3 months and maintained pad-free continence at 12 months. No significant difference was reported in median Trial Outcomes Index scores between baseline and 12 months (p=0·113) but significant improvement was shown in median Functional Assessment of Cancer Therapy (FACT)-Prostate (p=0·045) and median FACT-General scores (p=0·041). No histological evidence of cancer was identified in 30 of 39 men biopsied at 6 months (77%, 95% CI 61-89); 36 (92%, 79-98) were free of clinically significant cancer. After retreatment in four men, 39 of 41 (95%, 95% CI 83-99) had no evidence of disease on multiparametric MRI at 12 months. INTERPRETATION: Focal therapy of individual prostate cancer lesions, whether multifocal or unifocal, leads to a low rate of genitourinary side-effects and an encouraging rate of early absence of clinically significant prostate cancer. FUNDING: Medical Research Council (UK), Pelican Cancer Foundation, and St Peters Trust.