Diffusion-weighted MR imaging in early assessment of tumor response to radiotherapy in high-risk prostate cancer - Abstract

Objectives: The objective of this study was to assess the efficacy of diffusion-weighted MRI (DWI) in monitoring the response to radiotherapy in high-risk prostate cancer.

Materials and Methods: This retrospective study included 78 patients with high-risk prostate cancer undergoing 3.0 T MRI (supplemented by DWI) before and after Intensity Modulated Radiotherapy (IMRT). Based on follow-up clinical exams, patients were divided into two groups: the recurrence group (patients suffered biochemical/clinical recurrence within 3 years, n=13) and non-recurrence group (patients with over 3-years of recurrence-free, n=65). The apparent diffusion coefficient?ADC?values pre- and post-IMRT were compared between these two groups. The receiver-operating characteristics (ROC) analysis was carried out to investigate the discriminatory capability for pre- and post-IMRT ADC values.

Results: The overall ADC values were 1.04± 0.18×10-3mm2/s for prostate cancers before IMRT, and 1.45± 0.15×10-3mm2/s after IMRT (P< 0.001). A statistically significant difference in post-IMRT ADC values was noted between patients with and without recurrence (1.27 ± 0.14×10-3 mm2/s vs. 1.49 ± 0.12×10-3mm2/s, P< 0.001), though there was no statistical difference between them in pre-IMRT ADC values (1.00 ± 0.17×10-3mm2/s vs. 1.05 ± 0.18×10-3mm2/s, P=0.31). ROC curve analysis revealed that the post-IMRT ADC values could help identify patients suffering recurrences (area under the curve 0.88, P< 0.001)

Conclusions: Marked increase in ADC values was observed in prostate cancer after radiotherapy, especially in good responders. DWI is a valuable tool for monitoring the response to radiotherapy.

Advances in Knowledge: This study examined the relationship between ADC changes and tumor response to treatment in prostate cancer.

Written by:
Liu L, Wu N, Ouyang H, Dai JR, Wang WH.   Are you the author?
Department of Diagnostic Radiology, Cancer Hospital, Chinese Academy of Medical Sciences, Beijing 100021, China.

Reference: Br J Radiol. 2014 Aug 27:20140359.
doi: 10.1259/bjr.20140359

PubMed Abstract
PMID: 25162831

UroToday.com Prostate Cancer Section