mFOLFOXIRI Versus mFOLFOX6 as Adjuvant Chemotherapy for Locally Advanced Colorectal Cancer

The current standard treatment for locally advanced rectal cancer is still fluorouracil-based neoadjuvant radiotherapy and chemotherapy followed by TME surgery, followed by adjuvant chemotherapy. Fluorouracil single-agent simultaneous sensitization of radiotherapy and chemotherapy has a pCR of about 15-20% and a tumor downgrade (ypStage 0-I) rate of about 35%. However, about 30% of patients still have distant metastasis, which is the main obstacle affecting the survival prognosis of patients with locally advanced rectal cancer. About 50% -65% of patients was still stage II-III after neoadjuvant therapy. The long-term follow-up shows that for patients with ypT4 after surgery, the 3-year DFS is about 50%. For patients with ypN2, the 3-year DFS is less than 40%. Therefore, it is necessary to strengthen postoperative adjuvant chemotherapy to improve the survival prognosis for these patients. Although FOLFOX adjuvant chemotherapy improved survival benefit than 5FU as adjuvant treatment in ypStage II-III patients after neoadjuvant treatment in ADORE trial. However, with the progress of neoadjuvant therapy research, more and more studies have proposed to move part or all of postoperative adjuvant chemotherapy to preoperative neoadjuvant therapy due to low compliance of adjuvant chemotherapy. During neoadjuvant treatment, induction chemotherapy with FOLFOX / CAPEOX or consolidation therapy after CRT with FOLFOX / CAPEOX had been investigated a lot. The pCR rate was 19% -38%, and the tumor downstaging rate was about 50%. Another 50% of patients still had ypstage II-III postoperatively. The 3-year DFS for ypStage III was only 55% even with FOLFOX as adjuvant chemotherapy. And for ypT4N0 patients with ypstage IIB-IIC, there is also a higher risk of recurrence and metastasis. And it is urgent to explore new treatment strategies to improve this part of patients Survival prognosis. For locally advanced colon cancer, surgery combined with postoperative adjuvant chemotherapy is