Neoadjuvant Chemotherapy Alone With Mfolfoxiri In Locally Advanced Rectal Cancer: A Single-Arm Phase Ii Study.

TPS783 Background: Pre-operative 5-Fu based chemoradiation is still the standard of treatment for locally advanced rectal cancer (LARC). Although local recurrence rate had been controlled, about 30% of patients will develop distant metastases, which is the main obstacle for improving survival of LARC. Besides, preoperative radiation causes lots of concerns about anal and sexual functions. Whether systemic chemotherapy alone is effective enough in treating rectal cancer is not yet known. In our previous study of neoadjuvant mFOLFOX6 with or without radiotherapy in LARC, about 30% of patients in the arm with chemotherapy alone showed good response. And FOLFOXIRI had showed higher response rate in metastatic colorectal cancer. This phase II study is to explore whether pre-operative FOLFOXIRI could further improve the ratio of tumor downstaging (ypT0-2N0) in LARC. Methods: The primary endpoint is the ratio of tumor downstaging to ypT0-2N0M0 (pCR and stage I).The secondary endpoint included pathologic complete...