Evaluation of therapeutic response to concurrent chemoradiotherapy in patients with cervical cancer using diffusion-weighted MR imaging

Purpose: To investigate the changes in apparent diffusion coefficients (ADCs) in cervical cancer patients receiving concurrent chemoradiotherapy (CCRT), and to assess the relationship between tumor ADCs or changes in tumor ADCs and final tumor responses to therapy. Materials and Methods: Twenty-four patients with cervical cancer who received CCRT were examined with 3 Tesla (T) MRI including diffusion-weighted imaging (DWI). All patients had three serial MR examinations: before therapy (pre-Tx); at 4 weeks of therapy (mid-Tx); and 1 month after completion of therapy (post-Tx). At each examination, ADC was measured in tumors and normal gluteus muscles. Final tumor response as determined by change in tumor size or volume using MRI was correlated with tumor ADCs at each therapeutic time or changes in tumor ADCs at mid-Tx. Results: From pre-Tx to post-Tx, mean tumor ADCs were 0.88, 1.30, and 1.47 × 10 ^-3 mm²/s in sequence (P < 0.001), while those of normal gluteus muscles were 1.24, 1.29, and 1.21 × 10^-3 mm ²/s in sequence (P > 0.05). At mid-Tx, tumor ADCs and changes in tumor ADCs had a significant correlation with final tumor size responses (P = 0.029 and 0.025, respectively). However, the tumor ADC values at pre-Tx were not associated with the final tumor size response (P = 0.47). The final tumor volume response was not associated with tumor ADC at pre-Tx or mid-Tx (P > 0.05) or changes in tumor ADCs at mid-Tx (P > 0.05). Conclusion: DWI may have potentials in evaluating the therapeutic response to CCRT in patients with cervical cancer. J. Magn. Reson. Imaging 2013;37:187-193. © 2012 Wiley Periodicals, Inc.