414P Long-term follow-up of the randomized trial of the conventional technique versus the no-touch isolation technique for primary tumor resection in patients with colon cancer ( JCOG1006)

The no-touch isolation technique (No Touch) aims to reduce cancer cells from the primary tumor site to the liver and other organs by preceding ligation of blood vessels that feed the primary tumor. We conducted a phase III trial (JCOG1006) to confirm the superiority of No Touch in patients with cT3/T4 colon cancer, with a primary endpoint of disease-free survival (DFS). The planned primary analysis at 3 years after the last patient-in failed to confirm the superiority of No Touch compared with conventional technique (Conventional). The present study aimed to compare No Touch and Conventional using long-term follow-up data with 6 years after the last patient-in. Eligibility criteria included histologically proven colon cancer; tumor located in the cecum, ascending, transverse, descending, sigmoid or rectosigmoid colon; clinical T3 or T4, N0-2, M0; patients aged 20-80 years. Patients were randomized preoperatively to either Conventional arm or No Touch arm. Operation was performed by open surgery. Patients with pathological stage III received adjuvant chemotherapy with capecitabine. Planned sample size was 850 to detect a hazard ratio (HR) of 0.732 in DFS with one-sided alpha of 5% and power of 80%. A total of 853 patients were randomized (Conventional: 427, No Touch: 426) between January 2011 and November 2015. The 6-year DFS were 70.3% and 69.4% in the Conventional arm and No Touch arm, respectively. The HR was 1.030(95% CI 0.813-1.304); therefore, the superiority of No Touch was not confirmed (p=0.60). The 6-year overall survival (OS), 6-year relapse-free survival (RFS) and 6-year liver-relapse-free survival (LRFS) are shown in the table.Table: 414PConventional (95% CI)No touch (95% CI)HR (95% CI)6-year DFS70.3% (65.7-74.4%)69.4% (64.8-73.6%)1.030 (0.813-1.304)6-year OS89.4% (86.0-92.0%)86.6% (82.9-89.5%)1.276 (0.902-1.807)6-year RFS78.9% (74.7-82.5%)75.0% (70.6-78.8%)1.209 (0.920-1.589)6-year LRFS85.1% (81.2-88.2%)80.2% (76.0-83.8%)1.311 (0.961-1.787) Open table in a new tab Long-term follow-up data did not support superiority of No Touch compared with Conventional in the patents with stage II and III colon cancer.