Usefulness of magnetic resonance volumetric evaluation in predicting response to preoperative concurrent chemoradiotherapy in patients with resectable rectal cancer

Conclusion: The MR volumetric examinations before and after chemoradiation demonstrated the significant difference of tumor volume and % volume reduction rate between patients whose tumors were down-staged and those that were not down-staged. The volume reduction rates were significantly different among groups according to Dworak's grades. However, the MR volumetric evaluation could not identify any differences between those patients having a complete histologic regression and those with residual disease.