Diffusion-weighted magnetic resonance imaging: a potential non-invasive marker of tumour aggressiveness in localized prostate cancer

deSouza, N.M.; Riches, S.F.; VanAs, N.J.; Morgan, V.A.; Ashley, S.A.; Fisher, C.; Payne, G.S.; Parker, C.

doi:10.1016/j.crad.2008.02.001

« Previous Next »Clinical Radiology
Volume 63, Issue 7 , Pages 774-782, July 2008

Diffusion-weighted magnetic resonance imaging: a potential non-invasive marker of tumour aggressiveness in localized prostate cancer

N.M. deSouza
- Institute of Cancer Research and Royal Marsden NHS Foundation Trust, UK
- Guarantor and correspondent: N.M. deSouza, MRI Unit, Institute of Cancer Research and Royal Marsden Hospital, Downs Road, Sutton, Surrey SM2 5PT, UK. Tel.: +44 20 8661 3119/3289; fax: +44 20 8661 0846.
S.F. Riches
- Institute of Cancer Research and Royal Marsden NHS Foundation Trust, UK
N.J. VanAs
- Academic Urology Unit, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, UK
V.A. Morgan
- Institute of Cancer Research and Royal Marsden NHS Foundation Trust, UK
S.A. Ashley
- Department of Computing, Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
C. Fisher
- Department of Histopathology, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, UK
G.S. Payne
- Institute of Cancer Research and Royal Marsden NHS Foundation Trust, UK
C. Parker
- Academic Urology Unit, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, UK

Received 20 November 2007; received in revised form 29 January 2008; accepted 6 February 2008.

Aim

To evaluate diffusion-weighted magnetic resonance imaging (DW-MRI) as a marker for disease aggressiveness by comparing tumour apparent diffusion coefficients (ADCs) between patients with low- versus higher-risk localized prostate cancer.

Method

Forty-four consecutive patients classified as low- [n=26, stageT1/T2a, Gleason score≤6, prostate-specific antigen (PSA)<10 (group 1)] or intermediate/high- [n=18, stage≥T2b and/or Gleason score≥7, and/or PSA>10 (group 2)] risk, who subsequently were monitored with active surveillance or started neoadjuvant hormone and radiotherapy, respectively, underwent endorectal MRI. T2-weighted (T2W) and DW images (5 b values, 0–800s/mm²) were acquired and isotropic ADC maps generated. Regions of interest (ROIs) on T2W axial images [around whole prostate, central gland (CG), and tumour] were transferred to ADC maps. Tumour, CG, and peripheral zone (PZ=whole prostate minus CG and tumour) ADCs (fast component from b=0–100s/mm², slow component from b=100–800s/mm²) were compared.

Results

T2W-defined tumour volume medians, and quartiles were 1.2cm³, 0.7 and 3.3cm³ (group 1); and 6cm³, 1.3 and 16.5cm³ (group 2). There were significant differences in both ADC_fast (1778±264×10⁻⁶ versus 1583±283×10⁻⁶mm²/s, p=0.03) and ADC_slow (1379±321×10⁻⁶ versus 1196±158×10⁻⁶mm²/s, p=0.001) between groups. Tumour volume (p=0.002) and ADC_slow (p=0.005) were significant differentiators of risk group.

Conclusion

Significant differences in tumour ADCs exist between patients with low-risk, and those with higher-risk localized prostate cancer. DW-MRI merits further study with respect to clinical outcomes.