Endoscopic Mucosal Resection Method Research Articles

Comparison of precutting endoscopic mucosal resection and endoscopic submucosal dissection for large (20-30mm) flat colorectal lesions.

The complete and safe removal of large (≥20mm) colorectal lesions is an area of concern. Endoscopic submucosal dissection (ESD) effectively removes these lesions compared with endoscopic mucosal resection (EMR). However, ESD requires advanced techniques, longer procedure time, and high cost. Precutting EMR (EMR-P) is a modified EMR method that overcomes the limitations of EMR. This study aimed to compare the efficacy and safety of EMR-P and ESD in large (20-30mm) flat colorectal lesions. This was a retrospective analysis of cases in which 20- to 30-mm flat colorectal lesions were resected at Seoul St. Mary's Hospital from January 2014 to December 2019. Propensity score matching was performed to control for possible confounders. Two hundred and ninety-nine patients were included in this study. After matching, 90 patients were assigned to each group. There were no significant difference in complete resection rates (92.2% vs 92.2%, P=1.000), en bloc resection rates (95.6% vs 97.8%, P=0.682), and mean size of lesions (22.9±3.1mm vs 23.0±3.1mm, P=0.867) between EMR-P and ESD. Procedure time was significantly shorter with EMR-P (11.0±6.5min vs 37.0±19.3min, P<0.001). The adverse events rate was not significantly different between both groups. No local recurrence occurred in both groups. Precutting EMR was not significantly different to ESD in terms of complete resection rate and en bloc resection rate for 20- to 30-mm flat colorectal lesions without fibrosis. Furthermore, EMR-P has shorter procedure time than ESD. EMR-P could be considered one of standard treatments for large flat colorectal lesions.

Efficacy of under-gel endoscopic mucosal resection method for colonic lesion extending into the diverticulum.

Underwater endoscopic mucosal resection (EMR) is currently performed in various situations [1] [2] [3] [4]. One advantage to using water is the buoyancy effect on the mucosa, which raises it from the deeper muscularis propria without submucosal injection [1]. However, it takes time to fill the intestinal tract with water, leading to an increased risk of peristalsis and abdominal distension. In addition, underwater EMR on lesions extending into narrow spaces can be difficult to snare because constant water pressure is required. Here, we present a case in which a colonic adenoma extending into the diverticulum was successfully resected using “under-gel EMR” via VISCOCLEAR, a gel product for endoscopic procedures (Otsuka Pharmaceutical Factory, Tokushima, Japan).

Anchoring the snare tip is a feasible endoscopic mucosal resection method for small rectal neuroendocrine tumors

Small rectal neuroendocrine tumors (NETs) can be treated using cap-assisted endoscopic mucosal resection (EMR-C), which requires additional effort to apply a dedicated cap and snare. We aimed to evaluate the feasibility of a simpler modified endoscopic mucosal resection (EMR) technique, so-called anchored snare-tip EMR (ASEMR), for the treatment of small rectal NETs, comparing it with EMR-C. We retrospectively evaluated 45 ASEMR and 41 EMR-C procedures attempted on small suspected or established rectal NETs between July 2015 and May 2020. The mean (SD) lesion size was 5.4 (2.2) mm and 5.2 (1.7) mm in the ASEMR and EMR-C groups, respectively (p = 0.558). The en bloc resection rates of suspected or established rectal NETs were 95.6% (43/45) and 100%, respectively (p = 0.271). The rates of histologic complete resection of rectal NETs were 94.1% (32/34) and 88.2% (30/34), respectively (p = 0.673). The mean procedure time was significantly shorter in the ASEMR group than in the EMR-C group (3.12 [1.97] vs. 4.13 [1.59] min, p = 0.024). Delayed bleeding occurred in 6.7% (3/45) and 2.4% (1/41) of patients, respectively (p = 0.618). In conclusion, ASEMR was less time-consuming than EMR-C, and showed similar efficacy and safety profiles. ASEMR is a feasible treatment option for small rectal NETs.

Endoscopic application of mussel-inspired phenolic chitosan as a hemostatic agent for gastrointestinal bleeding: A preclinical study in a heparinized pig model.

Marine mussels secrete adhesive proteins to attach to solid surfaces. These proteins contain phenolic and basic amino acids exhibiting wet adhesion properties. This study used a mussel-inspired hemostatic polymer, chitosan-catechol, to treat gastrointestinal bleeding caused by endoscopic mucosal resection in a heparinized porcine model. We aimed to evaluate the hemostatic efficacy and short-term safety of this wet adhesive chitosan-catechol. We used 15 heparinized pigs. Four iatrogenic bleeding ulcers classified as Forrest Ib were created in each pig using an endoscopic mucosal resection method. One ulcer in each pig was untreated as a negative control (no-treatment group). The other three ulcers were treated with gauze (gauze group), argon plasma coagulation (APC group), and chitosan-catechol hemostatic agent (CHI-C group) each. The pigs were sacrificed on Days 1, 5, and 10, and histological examination was performed (n = 5 per day). Rapid hemostasis observed at 2 min after bleeding was 93.3% (14/15) in the CHI-C group, 6.7% (1/15) in the no-treatment group, 13.3% (2/15) in the gauze group, and 86.7% (13/15) in the APC group. No re-bleeding was observed in the CHI-C group during the entire study period. However, a few re-bleeding cases were observed on Day 1 in the no-treatment, gauze, and APC groups and on Day 5 in the gauze and APC groups. On histological analysis, the CHI-C group showed the best tissue healing among the four test groups. Considering the results, chitosan-catechol is an effective hemostatic material with reduced re-bleeding and improved healing.

Recurrence After Endoscopic Mucosal Resection: Early and Late Incidence, Treatment Outcomes, and Outcomes in Non-Overt (Histologic-Only) Recurrence

Recurrence After Endoscopic Mucosal Resection: Early and Late Incidence, Treatment Outcomes, and Outcomes in Non-Overt (Histologic-Only) Recurrence

Comparison of conventional and modified endoscopic mucosal resection methods for the treatment of rectal neuroendocrine tumors.

Small rectal neuroendocrine tumors (NETs) confined to the submucosa are endoscopically resectable. Because most rectal NETs are submucosal tumors, conventional endoscopic mucosal resection (cEMR) may not result in a complete resection. This study investigated whether modified EMRs, namely endoscopic submucosal resection with ligation (ESMR-L), EMR with precutting (EMR-P), and strip biopsy are superior to cEMR for achieving histologically complete resection (HCR) of rectal NETs. Medical records of 215 patients who were treated with endoscopic resections for rectal NETs between January 2011 and July 2019 were retrospectively enrolled. Of the patients, 110, 33, 29, and 43 underwent cEMR, ESMR-L, EMR-P, and strip biopsy, respectively. For each method, HCR and en bloc resection rates, procedure times, and complication rates were measured. HCR was achieved with cEMR, EMR-P, ESMR-L, and strip biopsies for 74.5%, 90.9%, 93.1%, and 90.7% of cases, respectively. The HCR rate for cEMR was inferior to those of the modified EMRs (p = 0.045 for cEMR vs. EMR-P; p = 0.031 for cEMR vs. ESMR-L; p = 0.027 for cEMR vs. strip biopsy). Among the three modified EMRs, there was no significant difference in achieving HCR (p = 1.000). En bloc resection (p = 0.096) and complication rates (p = 0.071) were not significantly different among the four EMR methods, although EMR-P required the longest procedure time (p = 0.000). All three modified EMRs are superior to cEMR and are equally effective for achieving HCR of rectal NETs.

Mo1285 SAFETY AND EFFICACY OF MULTIBAND MUCOSECTOMY AND ENDOSCOPIC CAP RESECTION IN EARLY BARRETT’S NEOPLASIA: A SYSTEMATIC REVIEW AND META-ANALYSIS

Endoscopic cap resection (CAP-R) and Multiband mucosectomy (MBM) are the two most commonly used endoscopic mucosal resection (EMR) procedures for early Barrett’s neoplasia. MBM is a newer method of EMR that does not require submucosal lifting and is technically easier to perform that CAP-R. We performed a systematic review and meta-analysis to compare the overall safety and efficacy of both these procedures for early Barrett’s neoplasia. We conducted a comprehensive search of multiple electronic databases and conference proceedings including PubMed, EMBASE, Web of Science databases, Google Scholar and manual search of references (from inception through Oct 2019) to identify the studies reporting use of MBM and CAP-R for early Barrett’s neoplasia. The primary outcome was to evaluate the technical success of the procedures which was defined as complete endoscopic resection of a delineated focal lesion. The secondary outcome was to study overall, early and delayed adverse events related to the procedures. The meta-analysis was performed using Der Simonian and Laird random effect model. 15 studies (N=1176 and no. of lesions=1487) reporting on MBM and 15 studies (N=653 and no. of lesions=785) reporting on CAP-R were included in our final analysis. The mean age was 64 years and 61.8 years in MBM group and CAP-R group respectively. The pooled technical success rates were 99.1% (95% CI 96.76-100, I2=81.51) in MBM group versus 94.2% (95% CI 84.61-99.69, I2=93.45) in CAP -R group with p-value of 0.139. (Table 1) The total early adverse event rates were 9.41% (95% CI 1.97-20.39, I2= 292.37) in CAP-R group versus 5.87% (95% CI 2.61-10.02, I2=78.26) in MBM group with p-value of 0.458. (Table 2) The most common early adverse events were bleeding with 5.09% (95% CI 1.97-9.19, I2=79.59) in MBM group and 5.95% (95% CI 2.47-10.46, I2=92.7) in CAP-R group. The most common delayed adverse events were stricture formation with 10.99% (95% CI 5.67-17.53, I2=86.84) in MBM group and 3.03% (95% CI 0.39-7.2, I2=74.88) in CAP-R group. The mean procedure time for MBM was shorter (23.3 min; reported in six studies) as compared to CAP-R (29.31 min; reported in six studies). Significant heterogeneity was noted in in our meta-analysis. Although in our study, MBM had similar pooled technical success rate as CAP-R in early Barrett’s neoplasia (p-value =0.139) but procedure times were shorter as compared to CAP-R. Further large multicenter randomized controlled trials are needed for further validation of our findings.Table 2Forest Plot showing overall early adverse events of MBM and CAP-RView Large Image Figure ViewerDownload Hi-res image Download (PPT)

Anti-reflux mucosectomy using a cap-assisted endoscopic mucosal resection method for refractory gastroesophageal disease: a prospective feasibility study

Endoscopic therapy of gastroesophageal reflux disease (GERD) overcomes the "treatment gap" for patients with refractory GERD, who are not willing to go into surgery. We propose an easy and efficient technique that is referred to as anti-reflux mucosectomy (ARMS) using cap-assisted endoscopic mucosal resection (EMR-C) which could be called ARMS-C. This study aimed to investigate the short-term outcomes of ARMS-C in GERD patients. From December 2016 to February 2018, we performed ARMS-C in 33 patients with pathologic reflux disease and esophageal hypersensitivity. ARMS-C involved endoscopic mucosal resection at the circumference of the esophagogastric junction (EGJ), resulting in narrowing of the hiatal opening after healing. The GERD symptoms, 24-h pH monitoring results, manometry, endoscopy, and EGJ distensibility were compared before and after the procedure. Six months after ARMS-C, 63% of patients discontinued the use of pump inhibitors (PPIs), while 30% patients reduced their PPI dose. The GERD questionnaire scores significantly decreased after ARMS-C, from 11.0 to 6.0 (P < 0.001). The median DeMeester score and acid exposure time based on pH monitoring also improved after ARMS-C. Furthermore, the median flap valve grade and EGJ distensibility decreased from 3.0 to 1.0 (P < 0.001) and from 19.0 to 13.9 (P < 0.001), respectively. Two patients were treated with balloon dilation due to stricture, but no other serious adverse events were encountered. ARMS-C may be an effective and safe treatment method for GERD in terms of short-term outcomes.

Sa1962 THE HEMOSTATIC EFFECT OF MUSSEL-INSPIRED CATECHOL ADHESIVE SHEET AFTER MUCOSECTOMY INDUCED ULCER: PORCINE EXPERIMENT

Gastrointestinal bleeding is the common problem in daily clinical practice. InnoSEAL Plus® is a sheet-type hemostat that is made of a mussel-inspired catecholic adhesive material. It can stop a variety of bleedings in a coagulopathy independent manner. The aim of this study was to evaluate hemostatic efficacy of the catechol-adhesive sheet on gastric ulcer bleeding on porcine model. In a total of 15 pigs, iatrogenic ulcer bleedings were made using endoscopic mucosal resection method. Five minutes before intervention the pigs were given full weight-adjusted heparin. Four ulcer bleedings (Forrest Ib) were made per 1 pig, and one of them was not treated as a negative control (NC) group. The other ulcers were treated with gauze compression (GC), argon plasma coagulation (APC), and InnoSEAL Plus® respectively. Initial hemostasis and recurrent bleeding were recorded. Initial hemostasis achivement at 2 minutes after the treatment was 14 of 15 (93.3%) with InnoSEAL Plus group while 1 of 15 (6.7%) of NC group, 2 of 15 (13.3%) of GC group, and 13 of 15 (86.7%) of the APC group. There was no recurrent bleeding in InnoSEAL Plus® group. Recurrent bleedings were occurred in NC group (n=2), GC group (n=1), and APC group (n=2) on day 1. One in APC group also showed recurrent bleeding on day 5. InnoSEAL Plus® has hemostatic efficacy to stop Forrest I b bleeding in pigs receiving anticoagulant therapy. This could be new endoscopic treatment for GI bleedings.

Endoscopic submucosal dissection and endoscopic mucosal resection methods for the removal of large sessile polyps

In expert hands, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) methods can successfully and definitively treat large sessile polyps, thus, eliminating the need for segmental colectomy. The goal should be to utilize ESD whenever feasible as it yields an en bloc specimen. ESD methods can also be used to definitively treat superficial invasive colorectal cancers, which have a very low chance of lymph node involvement.

Mo2030 Comparison of Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection Method in Circumferential Esophageal Mucosal Resection in Minipig Model

Mo2030 Comparison of Endoscopic Submucosal Dissection and Endoscopic Mucosal Resection Method in Circumferential Esophageal Mucosal Resection in Minipig Model

EMR is not inferior to ESD for early Barrett's and EGJ neoplasia: An extensive review on outcome, recurrence and complication rates.

Background and study aims In recent years, it has been reported that early Barrett’s and esophagogastric junction (EGJ) neoplasia can be effectively and safely treated using endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD). Multiband mucosectomy (MBM) appears to be the safest EMR method. The aim of this systematic review is to assess the safety and efficacy of MBM compared with ESD for the treatment of early neoplasia in Barrett’s or at the EGJ. Methods A literature review of studies published up to May 2013 on EMR and ESD for early Barrett’s esophagus (BE) neoplasia and adenocarcinoma at the EGJ was performed through MEDLINE, EMBASE and the Cochrane Library. Results on outcome parameters such as number of curative resections, complications and procedure times are compared and reported. Results A total of 16 studies met the inclusion criteria for analysis in this study. There were no significant differences in recurrence rates when comparing EMR (10/380, 2.6 %) to ESD (1/333, 0.7 %) (OR 8.55; 95 %CI, 0.91 – 80.0, P = 0.06). All recurrences after EMR were treated with additional endoscopic resection. The risks of delayed bleeding, perforation and stricture rates in both groups were similar. The procedure was considerably less time-consuming in the EMR group (mean time 36.7 min, 95 %CI, 34.5 – 38.9) than in the ESD group (mean time 83.3 min, 95 %CI, 57.4 – 109.2). Conclusions The MBM technique for EMR is as effective as ESD when comparing outcomes related to recurrence and complication rates for the treatment of early Barrett’s or EGJ neoplasia. The MBM technique is considerably less time-consuming.

Endoscopic mucosal resection of flat and sessile colorectal adenomas: Our experience with long-term follow-ups

Endoscopic mucosal resection (EMR) or mucosectomy is a removing method of flat or sessile lesions, laterally spreading tumors and carcinoma of the colon or the rectum limited to mucosa or the surface part of the submucosa. The aim of the study was to estimate the efficacy and safety of EMR in removing flat and sessile colorectal adenomas. This prospective study involved 140 patients during the period of 8 years. A total of 187 colorectal adenomas were removed using the EMR method "inject and cut with snare". The approximate size of mucosectomised adenomas was 13.6 mm (from 8 mm to 60 mm). There was a total of 48 (25.7%) flat adenomas and 139 (74.3%) sessile adenomas, P < 0.01). Using "en bloc" and "piecemeal" resection, 173 (92.5%) and 14 (7.5%) of colorectal adenomas were removed, respectively. In all the cases, a complete removal of colorectal adenomas was achieved. Two (1.4%) patients had adenoma removal with intramucosal carcinoma each. In the average follow-up period of 21.2 +/- 17.8 months, 2 (1.4%) patients had adenoma relapse after EMR. Considering complications, there was bleeding in 1 (0.7%) patient with a big rectum adenoma removed with EMR. Furthermore, one (0.7%) patient had a postcoagulation syndrome after cecal adenoma was removed by EMR. EMR is an efficient, safe and minimally invasive technique of removing flat and sessile adenomas in the colon and the rectum, with a very low percentage of adenoma recurrence over a long period of monitoring.

A case of ascending colonic xanthoma presenting as a lateral spreading tumor.

Gastrointestinal xanthomas are characterized by foamy cytoplasmic cells containing lipid in lamina propria, and occur almost in the gastric mucosa. Colonic xanthomas have been described in rare case. All reported colonic xanthomas were located in rectosigmoid. Rectosigmoid xanthomas have tended to exhibit small polypoid lesion, on the contrary flat in stomach. We report a case of xanthoma on ascending colon presenting as a laterally spreading tumor resected by endoscopic mucosal resection method.

Endoscopic Resection with Cap-Assisted Endoscopic Mucosal Resection: The Expert's Approach

Endoscopic mucosal resection (EMR) technique with suction cap is a simpler and easier refinement of EMR methods. The technique requires a specialized transparent cap that is fitted to the tip of an endoscope. Here the EMR technique with suction cap is demonstrated. This article is part of an expert video encyclopedia.

Endoscopic resection (endoscopic mucosal resection/ endoscopic submucosal dissection) for superficial esophageal squamous cell carcinoma: Current status of various techniques

Endoscopic resection (ER) has been widely accepted as an effective and minimally invasive treatment for patients with superficial esophageal squamous cell carcinoma (SCC). Techniques of conventional endoscopic mucosal resection (EMR) were first developed for ER. There are three representative methods of conventional EMR: endoscopic esophageal mucosal resection (EEMR)-tube method, EMR using a cap-fitted endoscope (EMRC) method and two-channel EMR method. In the past decade, techniques of endoscopic submucosal dissection (ESD) have become established as standard methods of ER. ESD allows en bloc resection of a lesion, irrespective of the size and shape of the lesion. Recently, results of retrospective cohort studies confirming that ESD is superior to EMR as a curative treatment for superficial esophageal SCC have been reported. Representative knives that are now frequently used in esophageal ESD include Hook knife, Triangle tip knife, IT knife nano, Flush knife-BT, Dual knife, SB knife, and so on. Although there are various knives developed for ESD, the basic techniques for safe and effective ESD are the same.

Mo1418 Outcomes of Endoscopic Mucosal Resection for Large Sessile Polyps and LST of Colorectum

Outcomes of Endoscopic Mucosal Resection for Large Sessile Polyps and LST of Colorectum Dae Hwan Kang, Hyung Wook Kim*, Cheol Woong Choi, Su Bum Park, Young Mi Hong, Jong Kun Ha, Ji Hoon Yoon, Min Dae Kim Internal Medicine, Pusan National University School of Medicine, Yangsan, Republic of Korea; Internal Medicine, Bongseng Memorial Hospital, Busan, Republic of Korea Backgrounds and Aims: Recently, endoscopic submucosal dissection (ESD) developed as a procedure for en bloc removal of colorectal neoplastic lesions regardless of their localization or diameter. However, the ESD procedures are technically difficult and associated with more complication compared to conventional endoscopic mucosal resection (EMR). The aim of our study is to assess efficacy and safety of endoscopic resection techniques to remove large( 20mm in diameter) sessile polyps and Laterally spreading tumor. Methods: We have treated 66 large sessile polyp and laterally spreading tumors which were resected by endoscopically from February 2009 to March 2011. Among them 48 lesions were laterally spreading tumors (LSTs) and 18 lesions were sessile polyps over 20mm in diameter. We compared the rate of en bloc resection, residual tumor/recurrence and complications between EMR and ESD. Result: 66 patients were included (age: 61.4 11.4(30-82). M:41, F: 25). There were high incidence of advanced pathology (adenocarcinoma 30.3%, high grade dysplasia 36.4%) The number of patients allocated in EMR, EMR-P, ESD-S and only ESD were 9(13.6%), 41(62.1%), 9(13.6%), 7(10.6%) respectively. Overall en bloc resection rate was 50.0%(33/66) and en bloc resection rate appeared to be more observed in ESD group than other groups, but there were not significant differences (EMR 66.7%, EMR-P 43.9%, ESD-S 33.3%, ESD 85.7%, p 0.105). Perforation occurred in 3(4.5%)cases. During follow-up period, there was only 1(1.5%) recurrence Conclusion: Patients with large ( 20mm in diameter) sessile polyps and laterally spreading tumor have a high incidence of advanced pathology, but most of large colorectal neoplasia can be treated by conventional EMR technique. EMR methods with good feasibility may take a transitional role before initiating ESD method in the treatment of large colorectal neoplasia

314a: A Prospective Randomized Controlled Trial Comparing “0.4% Sodium Hyaluronate” Versus “Normal Saline Solution” for Endoscopic Submucosal Dissection in Gastric Neoplasia by Supervised Residents

Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) yields higher complete resection rates than conventional endoscopic mucosal resection methods. However, one of the problems with ESD is the difficulty of learning the procedure.

Endoscopic aspiration mucosectomy using a novel vibration hood

We recently reported the usefulness of three types of original prelooped caps: the irrigating prelooped cap [1], the two-channel prelooped hood [2], and the internally retained snare hood [3] for endoscopic aspiration mucosectomy (EAM). EAM is the simplest method of endoscopic mucosal resection (EMR) [1] [2] [3] [4] [5], but there is a risk of aspirating and perforating the full thickness of the gastric wall. To reduce the risk of such perforation, the resection is normally performed by strangulation with a snare using a light touch. Experience is needed to apply this light touch with just the right pressure, and it can be an uncertain process. In order to apply vibration during strangulation, a novel vibration hood has been developed that enables strangulation and resection of only the mucosal and submucosal layers, by vibrating the snare during strangulation to shake off the muscle layer and serous membrane ([Fig. 1]).

Predictors Related to Need for Additional Bleeding Control During Follow-Up Endoscopic Examination After Gastric Endoscopic Submucosal Dissection and Efficacy of Routine Preventive Electrocoagulation

Background and Aim: Many reports suggested that gastric endoscopic submucosal dissection (ESD) technique was associated with higher complication rate compared with conventional endoscopic mucosal resection methods, and immediate or delayed bleeding was a most common complication. Previous studies have also showed the association of several factors such as patient's age, size of specimen, location of the lesion with frequency of bleeding. The purpose of this study was to evaluate the risk factors for additional endoscopic bleeding control during follow-up endoscopy after routine post-ESD coagulation. Methods: We analyzed data of 194 consecutive patients with 216 gastric neoplastic lesions from March 2007 to November 2008. All patients underwent a strict preventive hemostasis with electrocoagulation using coagulation forceps for all visible vessles as well as active bleeding focuses in the resected area. Follow-up endoscopy was performed within 24 to 48 hours after gastric ESD to identify the presence of delayed bleeding. Additional endoscopic bleeding control was performed in cases of active oozing, spurting and exposed large vessels. Various factors related to patients, endoscopic findings, resected specimen and the histologic diagnosis were analyzed as potential risk factors. Results: Additional endoscopic bleeding control was performed in 30 gastric lesions (13.9% of all lesions and 14.4% of patients). Among 30 lesions, 13 lesions (6.0% of all lesions) presented as a significant bleeding, defined as Forrest classification Ia and Ib. Three patients (1.5% of all patients) developed delayed bleeding during 9∼13 days after the procedure. Cancerous lesion was significantly associated with higher rate of significant bleeding during follow-up endoscopy compared with benign lesions such as adenoma and hyperplasic polyp (P = 0.045). Other variables was not associated with frequency of additional bleeding control during follow-up endoscopy. Conclusion: Routine preventive electrocoagulation alleviate known risk factors for delayed bleeding after gastric ESD, and therefore may lead to a lower delayed bleeding rate. In the case of cancer compared with benign lesion, more strict preventive bleeding control may be required because of higher rate of delayed bleeding.