Combined-modality therapy of rectal cancer with irinotecan-based regimens.

There are two conventional treatments for clinically resectable rectal cancer. The first is surgery followed by postoperative combined-modality therapy if the tumor is T3 and/or N1/2. The second, if the tumor is ultrasound T3 or clinical T4, is preoperative combined-modality therapy followed by surgery and postoperative chemotherapy. There are a number of new chemotherapeutic agents that have been developed for the treatment of colorectal cancer. Phase I/II trials are examining the use of new chemotherapeutic agents in combination with pelvic radiation therapy, most commonly in the preoperative setting. There is considerable interest in integrating irinotecan (Camptosar) into preoperative combined-modality therapy regimens for rectal cancer. Based on these trials, the recommended regimen for patients who receive irinotecan-based combined-modality therapy is continuous infusion fluorouracil (5-FU), irinotecan, and pelvic radiation. New trials examining preoperative combined-modality therapy regimens substituting capecitabine (Xeloda) for continuous infusion 5-FU are in progress.