Dr. Ciombor on the Efficacy of Preoperative Chemoradiation in Rectal Cancer

Kristen K. Ciombor, MD, MSCI, an assistant professor of medicine in the Division of Hematology/Oncology, Department of Medicine at Vanderbilt University Medical Center, Vanderbilt-Ingram Cancer Center, discusses responses achieved with preoperative chemoradiation in patients with rectal cancer.

Patients who enrolled on the phase 3 RAPIDO trial (NCT01558921) were randomized to the experimental arm of short-course radiotherapy followed by chemotherapy before total mesorectal excision (TME), or the control arm of chemoradiation, TME, and adjuvant chemotherapy, Ciombor says. Nearly all patients in the study had a high chance of undergoing surgery and having an R0 resection, but the rate of pathologic complete response nearly doubled for patients in the experimental arm, Ciombor notes.

The primary end point of the study was disease-related treatment failure; this was statistically significantly better in the experimental arm, Ciombor explains. Additionally, distant metastases were less commonly observed in the experimental arm. More mature data are needed regarding locoregional progression, but at 3 years, no statistically significant difference was observed between the 2 arms. However, a slight trend toward increased rates of locoregional progression was noted in the experimental arm, Ciombor says. 

The overall survival rates in the experimental and control arms were 89.1% and 88.9%, respectively, at 3 years despite the high-risk patient population, Ciobmor concludes.