RT Journal Article SR Electronic T1 Diffusion-weighted MRI Provides a Useful Biomarker for Evaluation of Radiotherapy Efficacy in Patients with Prostate Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 5027 OP 5032 VO 37 IS 9 A1 XINGCHEN WU A1 PETRI REINIKAINEN A1 MIKA KAPANEN A1 TUULA VIERIKKO A1 PERTTI RYYMIN A1 PIRKKO-LIISA KELLOKUMPU-LEHTINEN YR 2017 UL http://ar.iiarjournals.org/content/37/9/5027.abstract AB Background: Diffusion-weighted imaging (DWI) with measurement of apparent diffusion coefficient (ADC) allows for assessment of tumor aggressiveness. The objective of this study was to evaluate the changes of ADC value in prostate cancer after volumetric-modulated arc radiotherapy (VMAT) and to identify magnetic resonance imaging (MRI) biomarkers for monitoring tissue changes after radiotherapy. Patients and Methods: Thirty-seven patients with biopsy-proven prostate cancer treated with VMAT underwent serial MRI examinations including DWI before radiotherapy, and at 3 and 12 months after radiotherapy. ADC values of the tumor and healthy prostate tissue were measured and compared at these three time points. Results: The tumor ADC value increased significantly 3 months after radiotherapy (p<0.0001). There was a further increase of tumor ADC from 3 to 12 months after radiotherapy (p<0.01). The ADC of healthy prostate tissue did not show any significant changes. Conclusion: The ADC value is a useful biomarker for evaluating the efficacy of radiotherapy in prostate cancer.