Short-course Radiotherapy (5×6Gy/7Gy/8Gy) Followed by Neo-adjuvant Chemotherapy for Locally Advanced Rectal Cancer

Preoperative radiotherapy followed by total mesorectal excision (TME) has been recommended as the preferred treatment method for locally advanced rectal cancer. Similar rates of local control, survival and toxicity were observed in preoperative long-course radiotherapy (LCRT) (45-50.4 Gy in 25-28 fractions) and short-course radiotherapy (SCRT) of 25 Gy in five fractions. For the convenience of SCRT, a growing number of patients tend to receive SCRT as preoperative radiotherapy. Although SCRT can shorten treatment interval and cut down the cost of treatment, it's pathological complete response (pCR) rate is relatively low (SCRT vs. LCRT: 0.7% vs. 16%). Hence, the optimal pattern of preoperative therapy of locally advanced rectal cancer still deserves to be explored. Previous studies have confirmed the feasibility and safety of 30Gy/5 fractions in SCRT of rectal cancer and verified that SCRT followed by mFOLFOX6 chemotherapy can improve the pCR rates. Therefore, investigators aimed to establish a dose escalation mode of SCRT (5×6Gy/7Gy/8Gy) followed by four cycles of modified FOLFOX6(mFOLFOX6) chemotherapy to test the safety and efficacy in treating locally advanced rectal cancer.