Indications for and Technical Aspects of Colorectal Endoscopic Submucosal Dissection

Due to the widespread acceptance of gastric and esophageal endoscopic submucosal dissections (ESDs), the number of medical facilities that perform colorectal ESDs has grown and the effectiveness of colorectal ESD has been increasingly reported in recent years. The clinical indications for colorectal ESD at the National Cancer Center Hospital, Tokyo, Japan include laterally spreading tumor (LST) nongranular type lesions >20 mm and LST granular type lesions >30 mm. In addition, 0-IIc lesions >20 mm, intramucosal tumors with nonlifting signs and large sessile lesions, all of which are difficult to resect en bloc by conventional endoscopic mucosal resection (EMR), represent potential candidates for colorectal ESD. Rectal carcinoid tumors less than 1 cm in diameter can be treated simply, safely, and effectively by endoscopic submucosal resection using a ligation device and are therefore not indications for ESD. The en bloc resection rate was 90%, and the curative resection rate was 87% for 806 ESDs. The median procedure time was 60 minutes, and the mean size for resected specimens was 40 mm (range, 15 to 150 mm). Perforations occurred in 23 (2.8%) cases, and postoperative bleeding occurred in 15 (1.9%) cases, but only two perforation cases required emergency surgery (0.25%). ESD was an effective procedure for treating colorectal tumors that are difficult to resect en bloc by conventional EMR. ESD resulted in a higher en bloc resection rate as well as decreased invasiveness in comparison to surgery. Based on the excellent clinical results of colorectal ESDs in Japan, the Japanese healthcare insurance system has approved colorectal ESD for coverage.

Clinicopathologic Characteristics of Laterally Spreading Tumors in Colorectum / 대한소화기내시경학회지

BACKGROUND/AIMS: Among colorectal neoplasms, laterally spreading tumors (LSTs) are defined as tumors over 10 mm in diameter that are low in height and grow superficially. We analyzed the clinicopathologic characteristics of LSTs in colorectum. METHODS: Forty six LSTs were analyzed according to their endoscopic and pathologic findings. RESULTS: Incidence of LSTs were 2.0% (46/2,276). Twenty two LSTs (47.8%) were less than 20 mm in diameter, 20 (43.5%) were 20-30 mm, 4 (8.7%) were larger than 30 mm. The most frequent location was rectosigmoid colon (54.3%), followed by ascending colon (21.7%). Morphplogic types were GH types 37.0% (17/46), MN types 30.4% (14/46) and F types 32.6% (15/46). Histologic types were tubular adenomas 65.2% (30/46), tubulovillous adenomas 26.1% (12/46) and villous adenomas 8.7% (4/46). The overall malignancy rate was 19.6% (9/46). Malignancy rates were 4.5% (1/22) in the lesions less than 20 mm, 30.0% (6/20) in 20-30 mm, 50.0% (2/4) in larger than 30 mm. Malignancy rates were 11.8% (2/17) in GH type, 21.4% (3/14) in NM type and 26.7% (4/15) in F type. Carcinoma invaded into the submucosa were present in one lesion of NM types and two of F type. CONCLUSIONS: LSTs larger than 20 mm had high malignant potential, more than 30%. Furthermore, LSTs showed different clinicopathologic characteristics depending on the morphologic classification. NM or F type had higher malignant potential than GH type.

Endoscopic Characteristics and Management of

PURPOSE: A laterally spreading tumor (LST) has its own characteristic features and growth pattern. Information about LST is scanty in Korea, therefore this study was designed in order to contribute to the literature. METHODS: In this study, 43 patients with LSTs were included. The diagnoses were made by colonoscopy in all cases. Treatment options included endoscopic resection, transanal excision, and surgical resection. In reviewing and analyzing the cases, we made a special emphasis on size, classification, histology, and treatment. RESULTS: The most frequent location was the rectum, followed by the sigmoid colon and the ascending colon in that order. Lesions smaller than 20 mm accounted for 69.8%. Granular homogeneous LSTs, 41.9%. Lesions larger than 20 mm, except granular homogeneous LSTs, showed an abrupt increase in malignancy rate. Tubular adenomas accounted for 65.1%. The overall malignancy rate was 20.9%, and the submucosal cancer rate, 9.3%. There were no malignancies in the granular homogeneous LSTs. The malignancy rate for the mixed-nodule type lesions was 33.3% (4/12), and the nongranular LSTs, 38.5% (5/13). Polypectomy was done in 37.2% of the lesions, endoscopic mucosal resection (EMR) in 16.3%, and endoscopic piecemeal mucosal resection (EPMR) in 16.3%. The overall endoscopic resection rate was 83.7% (36/43). EMR was applicable to lesions smaller than 20 mm, and EPMR to those larger than 20 mm. Transanal resection was done in 2 cases with lesions. Five cases were resected surgically. Four of them were submucosal invasive lesions, and one, a mucosal lesion which was wide and had initially been thought to be a submucosal cancer. There were two recurrences during the average 15-month follow-up period. The follow-up rate was 81.4% (35/43). Of these 2 recurring cases, one patient was treated endoscopically and the other, transanally. CONCLUSIONS: LSTs show different behavior depending on the endoscopic classification. Granular homogeneous LSTs are seldom larger than 30 mm and are good candidates for endoscopic treatment. The mixed-nodule type and the nongranular type show a marked predisposition to malignancy when they are over 20 mm, and nongranular-type LSTs have a higher rate of submucosal invasive cancers. Thus, in the cases of the mixed-nodule and nongranular types, careful consideration should be given for deciding between endoscopic treatment and surgical resection. Complete resection should be assured to prevent recurrence, and follow-up surveillance is required in all lesions for more than 3 to 5 years.

Characteristics and Management of Laterally Spreading Tumors / 대한소화기내시경학회지

BACKGROUND/AIMS: Many endoscopists in Korea lack an understanding of laterally spreading, or creeping tumors(LSTs) which characteristically grow laterally, as opposed to other polypoid lesions, and which show superficially elevated lesions. An LST is similar in color to the adjacent normal mucosa, so it is difficult to recognize, but it can be detected by chromoscopy. When it grows to over 2-3 cm in its largest diameter, it can have malignant foci. It is important not to overlook the lesion and to remove it in a timely manner. METHODS: The authors experienced 9 cases of LSTs from Jan. 1996 to Jan. 1997. We reviewed those 9 cases clinically, endoscopically, and pathologically, and tried to establish the diagnostic and therapeutic key points. RESULTS: The most common age group was the fifth decade. The male-to-female ratio was 5:4. Four cases were asymptomatic, and lower abdominal pain and rectal bleeding were seen in 2 cases respectively. The rectum and the sigmoid colon were the most commonly involved sites showing 88.9% (8/9). Granular-type(nodule-aggregating-type) LSTs were seen in 4 cases and nongranular types(non-noodule-aggregating type) in 5 cases. 66.7%(6/9) were larger than 2 cm in the largest diameter. A tubular adenoma was seen in each of 5 cases; among them, 1 case had cellular atypia and another case revealed a submucosal(sm) carcinoma. Two granular types with large nodules had mucosal carcinomas. The sm carcinoma was a nongranular type. Endoscopically, redness was observed in 66.7%(6/9) of the cases and depression in 33.3%(3/9). The sm carcinoma had both redness and depression. Three cases underwent endoscopic piecemeal mucosal resection(EPMR) and the other 3 cases underwent endoscopic mucosal resection (EMR). A low anterior resection was performed on one patient; there was no lymph node metastasis. CONCLUSIONS: The characteristics of LSTs are important in their diagnosis and management. Nongranular-type LSTs are not uncommon, despite the difficulty in recognizing them by endoscopy. Pathologically, LSTs, in general, are tubular or tubulovillous adenomas. When they are over 2 cm in their largest diameter, they are likely to have malignancies. Giant nodule, redness and depression are important features indicating malignancy, especially an sm carcinoma. An EPMR or an EMR is the main treatment option, but depending on the depth of invasion, surgical resection may need to be considered.