494PShort-term clinical outcome from a randomized controlled trial of the conventional technique versus the no-touch isolation technique for primary tumor resection in patients with colon cancer: Japan Clinical Oncology Group study JCOG1006

Background: The no-touch isolation technique (NTIT) aims to reduce cancer cells flowing from the primary tumor site to liver and other organs by first ligation of blood vessels that feed the primary tumor. A previous randomized controlled trial (RCT) failed to prove its efficacy with statistical significance because of insufficient sample size and many patients being lost to follow-up. We conducted a phase III trial to confirm the superiority of NTIT in patients with cT3/T4 colon cancer. Methods: Eligibility criteria included histologically proven colon cancer; tumor located in the cecum, ascending, transverse, descending, sigmoid or rectosigmoid colon; T3 or T4; N0-2 and M0; patients age 20-80 years. Patients were randomized preoperatively to either conventional technique (CoT) arm or NTIT arm. Patients with pathological stage III received adjuvant chemotherapy with capecitabine. The primary endpoint was disease-free survival (DFS), and planned sample size was 850 to detect 6% difference in 3-year DFS with one-sided alpha of 5% and power of 80%. Short-term clinical outcomes were compared between the arms. (UMIN-CTR: UMIN000004957). Results: A total of 853 patients were randomized (CoT: 427, NTIT: 426) between January 2011 to November 2015. Conversion to CoT was needed for 5 (1.2%) patients in NTIT arm. Regarding surgical procedure, there were no differences in operative time (median 172 min: CoT, 178 min: NTIT, p=0.43), and in blood loss (median 69 ml: CoT, 77 ml: NTIT, p = 0.92). Postoperative complications and time to pass first flatus (median 2 days: CoT, 2 days: NTIT, p = 0.64) did not differ between the arms. There was no hospital death in both arms. Regarding radicality of surgery, there were no differences in D3 lymph node dissection rate (96.3%: CoT, 96.2%: NTIT) and pathological R0 resection rate (98.6%: CoT, 96.7%: NTIT). Conclusions: Operative quality, postoperative course, radicality, morbidity and mortality are similar in two arms. The primary analysis planned for 2019 is pivotal to prove superiority of NTIT to CoT in term of DFS. Clinical trial identification: UMIN-CTR: UMIN000004957 Legal entity responsible for the study: National Cancer Center Funding: National Cancer Research and Development Fund (26-A-4, 29-A-3) Disclosure: All authors have declared no conflicts of interest.