LAUSR

AIM The treatment strategies for T1 colorectal cancer (CRC) include both surgical and endoscopic resection. Surgical resection is indicated if lymphovascular invasion is present; however, the endoscopic prediction of lymphovascular invasion has not been reported. We aimed to correlate endoscopic morphology with pathological findings, including lymphovascular invasion, in non-polypoid T1 CRC. MATERIALS AND METHODS We retrospectively investigated 63 patients with non-polypoid T1 CRC surgically resected between 2008 and 2016. Four typical endoscopic findings related to deep submucosal invasion, namely protrusion from a depressed surface, fold convergence, fullness and hardness, were assessed to elucidate their association with pathological findings. RESULTS Protrusion was the only finding significantly correlated with positive venous invasion (67.9% of the lesions with protrusion vs. 34.3% of those without protrusion, p=0.01), which was also confirmed by a multivariable analysis (odds ratio(OR)=3.72, 95% confidence interval(CI)=1.24-11.2, p=0.02). CONCLUSION The endoscopic finding of protrusion on a depressed surface may be a sign indicating venous invasion in non-polypoid T1 CRC.