[Imaging evaluation of response of rectal cancer to preoperative chemoradiotherapy]

In recent years, preoperative therapy has become the standard procedure to improve radical resection rate and local control for advanced rectal cancer. Tumor responses to chemoradiotherapy, however, vary considerably, thus increasing the demand for both functional and morphologic radiologic evaluation of response to chemoradiotherapy to distinguish responders from nonresponders. MR imaging is considered the most accurate tool for the primary staging of tumor extent, and can be used to evaluate the efficacy of chemoradiotherapy. Functional imaging modalities including DW-MRI and PET-CT have shown promising prospect in the early evaluation of the response of rectal cancer to preoperative chemoradiotherapy. However, wide clinical application will take some time.