Long-term outcomes of intraoperative chemotherapy with 5-FU for colorectal cancer patients receiving curative resection (IOCCRC): a randomized, multicenter, prospective, phase III trial

Background: We aimed to compare combined intraoperative chemotherapy and surgical resection with curative surgical resection alone in colorectal cancer patients. Methods: We performed a multicenter, open-label, randomized, phase III trial. All eligible patients were randomized and assigned to intraoperative chemotherapy and curative surgical resection or curative surgical resection alone (1:1). Survival actualization after long-term follow-up was performed in patients analyzed on an intention-to-treat basis. Results: From January 2011 to January 2016, 696 colorectal cancer patients were enrolled and randomly assigned to intraoperative chemotherapy and radical surgical resection (n=341) or curative surgical resection alone (n=344). Intraoperative chemotherapy with surgical resection showed no significant survival benefit over surgical resection alone in colorectal cancer patients (3-year DFS: 91.1% vs. 90.0%, P =0.328; 3-year OS: 94.4% vs. 95.9%, P =0.756). However, colon cancer patients benefitted from intraoperative chemotherapy, with a relative 4% reduction in liver and peritoneal metastasis (HR=0.336, 95% CI: 0.148-0.759, P =0.015) and a 6.5% improvement in 3-year DFS (HR=0.579, 95% CI: 0.353-0.949, P =0.032). Meanwhile, patients with colon cancer and abnormal pretreatment CEA levels achieved significant survival benefits from intraoperative chemotherapy (DFS: HR=0.464, 95% CI: 0.233-0.921, P =0.029 and OS: (HR=0.476, 95% CI: 0.223-1.017, P =0.049). Conclusions: Intraoperative chemotherapy showed no significant extra prognostic benefit in total colorectal cancer patients who underwent radical surgical resection; however, in colon cancer patients with abnormal pretreatment serum CEA levels (> 5 ng/ml), intraoperative chemotherapy could improve long-term survival.