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.
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.