Totally neoadjuvant chemoradiation therapy with mFOLFOX6 in locally advanced rectal cancer: A single arm phase II study (FOTAC).

732Background: In our previous FOWARC study, in the group of preoperative systemic chemotherapy with mFOLFOX6 combined with radiation, the pCR rate was up to 27.5%. In another study, adding mFOLFOX6 after neoadjuvant chemo radiation in locally advanced rectal cancer improve the pCR rate to 38%. This phase II study aimed to explore whether totally neoadjuvant chemoradiation therapy with mFOLFOX6 could further improve the pCR rate in locally advanced rectal cancer. Methods: Patients with fixed cT3 or cT4 rectal cancer evaluated by pelvic MRI participated in this trial. All candidates were to receive long term radiation for 25 times and 50Gy before surgery. Four cycles of mFOLFOX6 would be performed every 2 weeks during radiotherapy, and another 4-6 cycles would be added after radiotherapy and before TME. Totally, the patients will receive 6-8 cycles of chemotherapy before surgery. The primary endpoint is the pathologic complete response rate (pCR).The secondary endpoint included 3-year disease free survival...