Nine-year Follow-up for a Study of Diffusion-weighted Magnetic Resonance Imaging in a Prospective Prostate Cancer Active Surveillance Cohort.
In active surveillance (AS) for prostate cancer there are few data on long-term outcomes associated with novel imaging markers.



To determine long-term outcomes with respect to the apparent diffusion coefficient (ADC) derived from diffusion-weighted magnetic resonance imaging (DW-MRI) in a prospective AS cohort. Early results have already been published; we now present findings with long-term follow-up.



A subset of patients (n=86) underwent pre-enrolment DW-MRI in a prospective AS study between 2002 and 2006. Inclusion criteria were untreated prostate cancer, clinical T1/T2a/N0M0, Gleason ≤ 3+4, and prostate-specific antigen (PSA) <15 ng/ml. Protocol follow-up was by biopsy at 18-24 mo and then every 24 mo, with regular PSA measurement.



Men underwent baseline DW-MRI in addition to standard sequences. ADC was measured from the index lesion on T2-weighted images. To avoid influencing treatment decisions, DW-MRI sequence results were not available to the AS study investigators.



Baseline ADC was analysed with respect to time to radical treatment (TRT) and time to adverse histology (TAH). Kaplan-Meier analysis and univariate and multivariate regression analyses were performed.



The median follow-up was 9.5 yr (interquartile range 7.9-10.0 yr). On univariate analysis, ADC below the median was associated with shorter TAH (hazard ratio [HR] 2.13, 95% confidence interval [CI] 1.17-3.89; p<0.014) and TRT (HR 2.54, 95% CI 1.49-4.32; p<0.001). Median TRT was 9.3 yr (95% CI 7.0-11.6 yr) for patients with ADC above the median and only 2.4 yr (95% CI 1.5-6.0 yr) for ADC below the median. For TRT, addition of ADC to a multivariate model of baseline variables resulted in a significant improvement in model fit (HR 1.33, 95% CI 1.14-1.54; p<0.001). Receiver operating characteristic analysis for TRT revealed an area under the curve of 0.80 (95% CI 0.70-0.88). The number of variables included in the multivariate model was limited by sample size.



Long-term follow-up for this study provides strong evidence that ADC is a useful marker when selecting patients for AS. Routine DW-MRI is now being evaluated in our ongoing AS study for initial assessment and as an alternative to repeat biopsy.



Before entering a study of close monitoring for the initial management of prostate cancer, patients had a type of magnetic resonance imaging scan that looks at the movement of water within cancers. These scans may help in predicting whether patients should receive close monitoring or whether immediate treatment should be given.
Academic Urology Unit, Royal Marsden NHS Foundation Trust, London, UK; Institute of Cancer Research, London, UK.
Daniel R
DR
Henderson
Institute of Cancer Research, London, UK; Department of Radiology, Royal Marsden NHS Foundation Trust, London, UK.
Nandita M
NM
de Souza
Academic Urology Unit, Royal Marsden NHS Foundation Trust, London, UK.
Karen
K
Thomas
Institute of Cancer Research, London, UK; Department of Radiology, Royal Marsden NHS Foundation Trust, London, UK.
Sophie F
SF
Riches
Institute of Cancer Research, London, UK; Department of Radiology, Royal Marsden NHS Foundation Trust, London, UK.
Veronica A
VA
Morgan
Institute of Cancer Research, London, UK; Department of Radiology, Royal Marsden NHS Foundation Trust, London, UK.
Syed A
SA
Sohaib
Academic Urology Unit, Royal Marsden NHS Foundation Trust, London, UK; Institute of Cancer Research, London, UK.
David P
DP
Dearnaley
Academic Urology Unit, Royal Marsden NHS Foundation Trust, London, UK; Institute of Cancer Research, London, UK.
Christopher C
CC
Parker
Academic Urology Unit, Royal Marsden NHS Foundation Trust, London, UK; Institute of Cancer Research, London, UK. Electronic address: nicholas.vanas@rmh.nhs.uk.
Nicholas J
NJ
van As
D000230:Adenocarcinoma / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D000368:Aged; D019540:Area Under Curve; D001706:Biopsy; D001918:Brachytherapy; D038524:Diffusion Magnetic Resonance Imaging; D018450:Disease Progression; D005500:Follow-Up Studies; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D016016:Proportional Hazards Models; D011446:Prospective Studies; D011467:Prostate / Q000000981:diagnostic imaging / Q000473:pathology; D017430:Prostate-Specific Antigen / Q000097:blood; D011468:Prostatectomy; D011471:Prostatic Neoplasms / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D012372:ROC Curve; D013997:Time Factors; D057832:Watchful Waiting / Q000379:methods*
D017430:Prostate-Specific Antigen
Active surveillance; Apparent diffusion coefficient; Diffusion weighting; Magnetic resonance imaging; Prostate cancer