Naoya Toyoshima

New closure technique for large mucosal defects after endoscopic submucosal dissection of colorectal tumors (with video)

BACKGROUND Certain large colorectal tumors satisfy expanded indications for endoscopic submucosal dissection (ESD); however, the resulting large mucosal defects may contribute to complications such as delayed bleeding and perforation. Various closure devices and methods have been developed for large mucosal defects to prevent such complications. OBJECTIVE To demonstrate the feasibility of a new and simple technique for closing large mucosal defects after colorectal ESD. DESIGN Pilot feasibility study. SETTING Single center. PATIENTS Ten patients with 10 tumors half circumferential or less in size with sufficient muscle layer exposure after ESD were selected and treated by using the closure technique between July 2009 and June 2010. INTERVENTION Small mucosal incisions were made around the mucosal defect by the same needle-knife used during ESD. These incisions provided a better grip for conventional clips, which then facilitated lifting the surrounding mucosa across the defect without slipping, thereby making it considerably easier to reduce the size of the defect and place additional clips. MAIN OUTCOME MEASUREMENTS Patient characteristics and tumor clinicopathologic features were assessed as well as closure completion rate, closure procedure time, and closure-related complications. RESULTS All 10 tumors were successfully treated by ESD. Mean lesion size was 26.8 mm (range 8-50 mm). All mucosal defects were completely closed by using the new closure technique, without complications. Mean closure procedure time was 15 minutes (range 8-35 minutes). LIMITATIONS Small sample size with specifically selected patients. CONCLUSION Large mucosal defects resulting from colorectal ESD can be completely closed with small mucosal incisions by using conventional clips.

Clinicopathological features of T1 colorectal carcinomas with skip lymphovascular invasion

With recent advances in endoscopic treatment, many T1 colorectal carcinomas (CRCs) are resected endoscopically with a negative margin. However, some lesions exhibit skip lymphovascular invasion (SLVI), which is defined as the discontinuous foci of the tumor cells within the colon wall. The aim of the present study was to reveal the clinicopathological features of T1 CRCs with SLVI and validate the Japanese guidelines regarding SLVI. A total of 741 patients with T1 CRCs that were resected surgically between April 2001 and October 2016 in our hospital were divided into two groups: With SLVI and without SLVI. Clinicopathological features compared between the two groups were patients gender, age, tumor size, location, morphology, lymphovascular invasion, tumor differentiation, tumor budding and lymph node metastasis. The incidence of T1 CRCs with SLVI was 0.9% (7/741). All cases with SLVI were found in the sigmoid colon or rectum. T1 CRCs with SLVI showed significantly higher rates of lymphovascular invasion than those without SLVI (P<0.01). In conclusion, lymphovascular invasion was a significant risk factor for SLVI in T1 CRCs, and for which surgical colectomy was necessary. The Japanese guidelines are appropriate regarding SLVI. Registered in the University Hospital Medical Network Clinical Trials Registry (UMIN000027097).