['To determine if diffusion-weighted imaging (DWI) can be used as a surrogate marker of tumor response to anticancer therapy in patients with soft-tissue sarcomas.', 'Magnetic resonance imaging (MRI) including echo-planar DWI sequences was performed prospectively in 23 consecutive patients with soft-tissue sarcomas before and after initiation of regional or systemic chemotherapy. The mean interval between initial and follow-up MRI was 56.9 +/- 23.2 days. Tumor volumes were determined by manual segmentation of tumor borders on contrast-enhanced T1-weighted images. The apparent diffusion coefficient (ADC) was calculated from corresponding sections of ADC maps on initial and follow-up DWI. Subsequently, changes in tumor volumes and ADC were correlated using the Pearson correlation coefficient.', 'A high degree of correlation was found when changes in tumor volumes and ADC values were compared (r = -0.925, P < 0.0001), regardless of the effectiveness of anticancer therapy expressed as changes of tumor volume.'] Does diffusion-weighted magnetic resonance imaging allow monitoring of anticancer treatment effects in patients with soft-tissue sarcomas?