Diffusion-weighted magnetic resonance imaging for monitoring prostate cancer progression in patients managed by active surveillance

Abstract

Objectives: We studied patients managed by active surveillance to determine whether there was a difference over time in apparent diffusion coefficients (ADCs) derived from diffusion-weighted MRI in those who progressed to radical treatment (progressors, n517) compared with those who did not (non-progressors, n533). Methods: 50 consecutive patients (Stage T1/2a, Gleason grade # 3+4, prostate-specific antigen (PSA) ,15 ng ml -1 , ,50% cores positive) were imaged endorectally (baseline and 1-3 years follow-up) with T 2 weighted (T 2 W) and echo-planar diffusion-weighted MRI sequences. Regions of interest drawn on ADC maps with reference to the T 2 W images yielded ADC all (b50-800), ADC fast (b50-300) and ADC slow (b5300-800) for whole prostate (minus tumour) and tumour (low signal-intensity peripheral zone lesion in biopsy-positive octant). Results: Tumour and whole prostate ADC all and ADC fast were significantly reduced over time in progressors (p50.03 and 0.03 for tumours, respectively; p50.02 and 0.007 for the whole prostate, respectively). There were no significant changes in ADC over time in non-progressors. A 10% reduction in tumour ADC all indicated progression with a 93% sensitivity and 40% specificity (A z of receiver operating characteristic (ROC) curve 5 0.68). Percentage reductions in whole prostate ADC all , ADC fast and ADC slow were also significantly greater in progressors than in non-progressors (p50.01, 0.03 and 0.008, respectively).Conclusion: This pilot study shows that DW-MRI has potential for monitoring patients with early prostate cancer who opt for active surveillance.

Novel Tools to Improve Patient Selection and Monitoring on Active Surveillance for Low-risk Prostate Cancer: A Systematic Review

“…The literature search identified 30 original articles that were included for review: 14 on magnetic resonance imaging (MRI) [8][9][10][11][12][13][14][15][16][17][18][19][20][21], 5 on serum markers [22][23][24][25][26], 5 on urinary markers [27][28][29][30][31], 4 on histopathology markers [32][33][34][35], and 2 on germline genetic markers [36,37]. Figure 1 presents the search strategy and study selection flowchart.…”

“…At least one suspicious region (two in most patients) was identified in 98% of patients and biopsied. These MRI-guided biopsies to suspicious areas identified PCa in just over half the lesions Morgan et al analysed AS patients who all underwent 1.5-T DW-MRI both at inclusion and follow-up (n = 50) [21]. ADC of both tumour area and whole prostate decreased during follow-up of patients who showed disease progression.…”

Relationship betweenT2relaxation and apparent diffusion coefficient in malignant and non-malignant prostate regions and the effect of peripheral zone fractional volume

“…A radiologist with 15 years of experience in endorectal prostate MRI drew free-hand regions of interest (ROIs) around the PZ and TZ on a single slice of the axial T 2 W images at the level of the verumontanum ( Figure 1). Previous data have shown that ADCs measured in normal prostate regions from parameter maps generated in this way show minimal variation with time [14]. In addition, a free-hand ROI was placed on a single slice around a dominant tumour nodule (identified as an area of hypointense signal on the T 2 W images in a biopsy-positive octant on the slice where it appeared the largest) with simultaneous visual reference to the ADC maps.…”

Advanced Prostate Imaging: Correlating Prostate Anatomy with MRI and MRI/Ultrasound Fusion

“…Therefore, DWI provides us with distinct functional quantitative information that refl ects integrity of cellular membranes, cellular density, and extracellular space [ 15 ]. ADC is inversely correlated to Gleason score and is helpful in differentiating between low, intermediate and high-risk Gleason scores [ 16 ]. DWI also improves PCa detection when combined with T2WI, with described sensitivity and specifi city of 89 % and 91 %, respectively [ 17 ].…”