Predictors of Tumor Response and Downstaging in Patients Who Receive Preoperative Chemoradiation for Rectal Cancer.

The article presents a study which examined the predictive factors for pathologic complete response and tumor downstaging after preoperative chemoradiation for rectal cancer. The study employed 562 patients with nonmetastatic rectal adenocarcinoma who received preoperative chemoradiation and underwent mesorectal excision between 1989 and 2004. The study found that 19% of patients achieved a pathologic complete response, whereas 20% had only microscopic residual disease at surgery, and 61% had macroscopic residual disease at surgery.