Combined modality therapy of resectable rectal cancer: current approaches

There are two conventional treatments for clinically resectable rectal cancer. First is surgery and, if the tumor is in stage T3 or N1-2, this is followed by postoperative combined modality therapy. The second is preoperative combined modality therapy followed by surgery and postoperative combined modality therapy if the tumor is classified at ultrasound as uT3-4 or N+. A number of new chemotherapeutic agents have been developed for the treatment of patients with colorectal cancer. Ongoing phase I and II trials are examining the use of these new chemotherapeutic agents in combination with pelvic radiation therapy, most commonly in the preoperative setting; early results suggest that the complete response rates are higher. Based on results from phase I and II trials, the standard regimen for patients who receive combined modality therapy is continuous infusion 5-fluorouracil (5-FU) and pelvic radiation. Regimens using CPT-11 or oxaliplatin-based combined modality therapy plus either continuous infusion 5-FU or capecitibine are under active development.