**3. ESD technique**

ESD for colorectal tumors has been considered more technically demanding as compared to that in the stomach. This can be attributed to these following reasons: (1) thinner and softer colonic wall, (2) endoscopic control is difficult in specific parts of the colon due to paradoxical movement; (3) limitations to the retroflexed approach due to the narrow caliber of the colon; (4) tumours located on or behind a prominent colonic folds, peristalsis, and (5) higher risk of diffuse peritonitis requiring emergency surgical intervention as compared to perforation of the upper gastrointestinal tract. [34]

Several devices have been applied to ESD in the colon and rectum with the principle to use a dissecting technique that allows direct visualization of the submucosal tissue, and to use longlasting injecting fluid. [79-80]

#### **3.1. Technical method**

#### *3.1.1. Approach strategy and technique for mucosal incisions and submucosal dissection*

Success of the ESD procedure lies with the maneuverability and stability of the endoscope. Hence, the insertion must be done in a controlled manner to avoid loop formation if possible. Authors have reported that rotation is a key movement. Upon reaching the tumor, the lumen of the intestine is filled with a mixture of water and simethicon to ensure adequate visualiza‐ tion. Chromoendoscopy with indigo carmine is performed to characterize the surface details and extent of the lesion. The borders of the lesion should be clearly visualized. [34]

A good strategy with prior considerations to the angle of approach to the lesion, taking into account the direction of gravity in relation its location is recommended. This can be assessed by observing the direction of the course of the jet stream of water from the water-jet. The position of the patient should be selected to locate the lesion at the top of the colonic lumen with regard to gravity. This enables sufficient opening of the mucosal incision and good visualization of the submucosal tissue during the procedure. Hence, minimal sedation for patient comfort is recommended if possible to allow patients to move positions more readily and report any undue discomfort during the procedure. In cases of unfavorable events such as bleeding and perforation, this positioning is beneficial to avoid or minimize further complications. In this position, bowel contents will not spill or leak into the intraperitoneal cavity and also, in situations of bleeding, blood will flow in the opposite direction (anti-gravity) to that of the lesion and not pool at the area of dissection. For example, if the bleeding point is at the top of the lumen, hemostasis can be performed reliably with accurate identification of the bleeding point because blood flows away from the bleeding point by gravity.

**Device Cut Mode Coagulation Mode**

Dry Cut E6 30 W

> Spray Coag E2 5 W Soft Coag E6 80 W

E1/D 4/11

Submucosal Dissection Flush knife Dry Cut E6 30 W Swift Coag E4 30 W

Minor bleeding and small blood vessels can be managed using the knife. However, more reliable hemostasis for a larger vessel can be achieved using hemostatic forceps (HDB2422W; Pentax, Tokyo, Japan). The generator is set to soft coagulation mode for the hemostatic forceps.

ESD for colorectal tumors has been considered more technically demanding as compared to that in the stomach. This can be attributed to these following reasons: (1) thinner and softer colonic wall, (2) endoscopic control is difficult in specific parts of the colon due to paradoxical movement; (3) limitations to the retroflexed approach due to the narrow caliber of the colon; (4) tumours located on or behind a prominent colonic folds, peristalsis, and (5) higher risk of diffuse peritonitis requiring emergency surgical intervention as compared to perforation of

Several devices have been applied to ESD in the colon and rectum with the principle to use a dissecting technique that allows direct visualization of the submucosal tissue, and to use long-

Success of the ESD procedure lies with the maneuverability and stability of the endoscope. Hence, the insertion must be done in a controlled manner to avoid loop formation if possible. Authors have reported that rotation is a key movement. Upon reaching the tumor, the lumen of the intestine is filled with a mixture of water and simethicon to ensure adequate visualiza‐ tion. Chromoendoscopy with indigo carmine is performed to characterize the surface details

A good strategy with prior considerations to the angle of approach to the lesion, taking into account the direction of gravity in relation its location is recommended. This can be assessed by observing the direction of the course of the jet stream of water from the water-jet. The

*3.1.1. Approach strategy and technique for mucosal incisions and submucosal dissection*

and extent of the lesion. The borders of the lesion should be clearly visualized. [34]

Effective control of bleeding during the procedure is a vital factor for successful ESD.

Mucosal Incision Flush knife Endo Cut I

106 Colonoscopy and Colorectal Cancer Screening - Future Directions

Hemostatic Forceps

**Table 2.** ERBE VIO 300D settings for ESD procedures (W: watts)

Hemostasis Flush knife

**3. ESD technique**

the upper gastrointestinal tract. [34]

lasting injecting fluid. [79-80]

**3.1. Technical method**

Even in cases of perforation, if the perforation occurs at the top of the lumen with regard to gravity, identification and closing of the perforation is easier, maintaining a good view of the site of perforation. Air, not contaminated intestinal fluid, will flow out from the lumen to the abdominal cavity before closing the perforation, which is important to prevent diffuse peritonitis.

The mucosal incision is made only in the area to be dissected. This is made with a short FlushKnife (1.5 mm; DK2618JN15; Fujifilm Corp., Tokyo, Japan) after sufficient protrusion of the mucosa is obtained with injection of suitable fluid. The Endo Cut mode is used for the mucosal incision. ESD can be performed safely with a FlushKnife as long as adequate thick‐ ening of the submucosal layer is present. This maintains a safety margin away from the muscle layer. The dissection should be done parallel to the muscular layer, by sliding the knife from the centre of the tumor toward the mucosal incision on the side, while hooking submucosal fibers with the knife. There are several other types of knives available commercially and several other techniques have been described in literature but these are not described here.

Several newer strategies have been introduced over the last couple of years. As shown in Figure 9(a) [SAFEKnife Horizontal®. DK2518DH1 Fujifilm Corp, Tokyo Japan] newer knives have been designed to enable a different axis of cutting. These are introduced during the submucosal dissection itself during the procedure with the aim to achieve maximal safety and efficacy.

The mucosal incision is made only in the area to be dissected and then dissection of the submucosa from the incised part is promptly started. Circumferential marking around the tumor with the tip of the electrosurgical knife is recommended for lesions in the upper gastrointestinal tract but not for intestinal neoplasms as the colonic wall is thin enough to be perforated in the process.

The development and subsequent maintenance of sufficient mucosal elevation is paramount for safe mucosal incisions and submucosal dissection. For these purposes, 0.4% sodium hyaluronate solution (MucoUp®; Seikagaku Corp, Tokyo, Japan) is the best injection fluid for ESD. [79-80]. The authors have found that the submucosal injection of sodium hyaluronate (0.4%) – commercially known as MucoUp®, (Johnson and Johnson Medical Co., Tokyo, Japan) enables the creation of a long-lasting mucosal protrusion that usually lasts more than 1 hour, providing the longest lasting fluid cushion, [49,79-80] and higher successful en-bloc resection

(a) (b)

This solution is injected into the submucosal layer just outside where the mucosal incision is

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The mucosal incision is made with a short FlushKnife® (1.5 mm; DK2618JN15; Fujifilm Corp., Tokyo, Japan) after sufficient protrusion of the mucosa is obtained. Only the needle part should be used for the incision, keeping the tip of the sheath touching the surface of the mucosa without pushing the sheath into the submucosal layer. The Endo Cut mode is used for the

There is no need for complete marginal cutting of the mucosa before the submucosal dissection. Some authors report that after exposure of the submucosal layer, with the visualization of the blue-stained submucosal connective tissue, further submucosal injection from the exposed submucosal layers may be used to elevate the layer that is to be cut. If the blue submucosal layers is not seen, this may indicate that the muscularis mucosae layers is incompletely cut and

ESD can be performed safely with a FlushKnife® as long as adequate thickening of the submucosal layer is present. This maintains a safety margin away from the muscle layer. The dissection should be done parallel to the muscular layer, by sliding the knife from the centre of the tumor toward the mucosal incision on the side, while hooking submucosal fibers with the knife. The submucosal fibres stained blue (indigo-carmine) are very soft and dissected easily with gentle application of the FlushKnife ® using the forced or swift coagulation mode. The knife length may be kept at the same length (<2mm) for both the mucosal incision and

A recent "tunneling" method has been introduced to dissect the submucosal layer, starting at the proximal edge of the colorectal tumour, followed by the distal edge.[34] Submucosal dissection is continued to make a tunnel in the submucosal layer by inserting the tip of the endoscope with a transparent hood under the mucosal tumor. This is continued to reach the mucosal incision at the proximal edge. After penetration of the tunnel, which began from both

the incising line should be traced again until the blue submucosal layer is seen.

**Figure 10.** (a): one vial of Optovisc® (b): Indigo Carmine Solution

intended.

*3.1.2. Mucosal incision*

*3.1.3. Submucosal dissection*

submucosal dissection.

mucosal incision, at 30 watts. (Table 2)

**Figure 9.** (a): SAFEKnife H ® that cuts in the horizontal plane and (b) SAFEKnife V ® that cuts in the vertical plane – invented by Dr H Yamamoto, manufactured by Fujifilm Corp Japan – 9(c) SAFEKnife V ® has a sandwichlike structure with a central electrode plate placed between 2 insulated plates enablising a safe and effective dieesction of the sub‐ mucosal layers with a vertical approach

and lower perforation complication rates have been reported using HA, particularly for colorectal ESD [31,44,47,53-54]. However, in view of its high cost and unavailability locally (US \$49.50–128.00/mL in the United States), we have created our own solution using (Fig 10ab) 4 vials of Optovisc Eyedrops® (Ashford, FP Marketing) (Fig 10a) to make up 40mls of solution. 0.4mls of 1:1000 Adrenaline with 4 drops of Indigo carmine solution (Fig 10b).

**Figure 10.** (a): one vial of Optovisc® (b): Indigo Carmine Solution

This solution is injected into the submucosal layer just outside where the mucosal incision is intended.

#### *3.1.2. Mucosal incision*

The mucosal incision is made with a short FlushKnife® (1.5 mm; DK2618JN15; Fujifilm Corp., Tokyo, Japan) after sufficient protrusion of the mucosa is obtained. Only the needle part should be used for the incision, keeping the tip of the sheath touching the surface of the mucosa without pushing the sheath into the submucosal layer. The Endo Cut mode is used for the mucosal incision, at 30 watts. (Table 2)

There is no need for complete marginal cutting of the mucosa before the submucosal dissection. Some authors report that after exposure of the submucosal layer, with the visualization of the blue-stained submucosal connective tissue, further submucosal injection from the exposed submucosal layers may be used to elevate the layer that is to be cut. If the blue submucosal layers is not seen, this may indicate that the muscularis mucosae layers is incompletely cut and the incising line should be traced again until the blue submucosal layer is seen.

#### *3.1.3. Submucosal dissection*

and lower perforation complication rates have been reported using HA, particularly for colorectal ESD [31,44,47,53-54]. However, in view of its high cost and unavailability locally (US \$49.50–128.00/mL in the United States), we have created our own solution using (Fig 10ab) 4 vials of Optovisc Eyedrops® (Ashford, FP Marketing) (Fig 10a) to make up 40mls of solution. 0.4mls of 1:1000 Adrenaline with 4 drops of Indigo carmine solution (Fig 10b).

**Figure 9.** (a): SAFEKnife H ® that cuts in the horizontal plane and (b) SAFEKnife V ® that cuts in the vertical plane – invented by Dr H Yamamoto, manufactured by Fujifilm Corp Japan – 9(c) SAFEKnife V ® has a sandwichlike structure with a central electrode plate placed between 2 insulated plates enablising a safe and effective dieesction of the sub‐

(a)

108 Colonoscopy and Colorectal Cancer Screening - Future Directions

(b)

(c)

mucosal layers with a vertical approach

ESD can be performed safely with a FlushKnife® as long as adequate thickening of the submucosal layer is present. This maintains a safety margin away from the muscle layer. The dissection should be done parallel to the muscular layer, by sliding the knife from the centre of the tumor toward the mucosal incision on the side, while hooking submucosal fibers with the knife. The submucosal fibres stained blue (indigo-carmine) are very soft and dissected easily with gentle application of the FlushKnife ® using the forced or swift coagulation mode. The knife length may be kept at the same length (<2mm) for both the mucosal incision and submucosal dissection.

A recent "tunneling" method has been introduced to dissect the submucosal layer, starting at the proximal edge of the colorectal tumour, followed by the distal edge.[34] Submucosal dissection is continued to make a tunnel in the submucosal layer by inserting the tip of the endoscope with a transparent hood under the mucosal tumor. This is continued to reach the mucosal incision at the proximal edge. After penetration of the tunnel, which began from both

used for moderate-sized lesions but with larger lesions, an over-tube may be required. The shape and orientation of the specimen is dutifully recorded, and the specimen pinned out on a Styrofoam or corkboard with the oral and anal sides indicated. The preservation of fresh material is ensured by freezing in liquid nitrogen, embedded in OCT prior to freezing, The slice is cut from the middle without warming up to allow a frozen section to be used for further analysis. We recommend the use of formalin soaked needles to fix the specimen, which should

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The ESD specimens are regarded as complex specimens and undergo a standardized process‐ ing during both macroscopic and microscopic assessment of the specimens. They are photo‐ graphed with a styrofoam backing board, with the oral side of the specimen "O" at 12 o'clock position, and the anal side "A" at the 6 o'clock position to ensure that the orientation of the

Since 2009 to 2011, the specimen has been processed as shown below: The principle is to enable a fairly precise assessment of margin involvement. Currently, there are 2 methods of section‐ ing, each having their advantages and disadvantages. The first is described below whereby each transverse section should be submitted separately. The smaller fragments from the lateral edges should be submitted no more than 2 pieces per block. This has been performed since January 2009. The disadvantage of this method is that rounded irregular edges of such specimen are inadvertently shaved off during each 2mm sectioning and these margins cannot be assessed accurately when the sections happen to be tangential to the edge. The second method of sectioning aims to overcome the above problem. The axis of sectioning is perpen‐ dicular to the tangential line drawn at the edge. (Fig 14) This will enable more accurate margin assessment although tissue loss at the apex of each "segment" is inevitable. Inking of the margins is necessary and different colour should be used to represent the respective margins

be tension-free as there is 20 to 50% shrinkage of the specimen soaked in formalin.

specimens are known. (Fig 12)

**Figure 13.** Mounting of a specimen on a Styrofoam board

as required.

**Figure 12.** En bloc resection of the entire lesion (68 × 62 mm in diameter). Histopathologic examination confirmed complete curative resection (adenocarcinoma in adenoma, no invasion to submucosa, no lymphatic or vascular in‐ volvement); © Photographs courtesy of H Yamamoto 2010

ends, it is widened laterally. The mucosa on both sides of the tumour is then incised laterally and dissected submucosally to complete the dissection. (Fig.11). This tunneling technique enables the endoscope tip to be stabilized, hence a more precise control of the Flushknife® is achieved. This technique also enables a good safety margin for further dissection by stretching the submucosal tissue. Adjusting the approach angle of the knife to be tangential to the wall also is easy with this method because an adjusting force with the endoscope tip can be applied in either direction by pushing the mucosa up or pushing the muscle wall down with the tip of the hood (Fig 11b). This method is particularly useful for large lesions, lesions with fibrosis, and lesions located on a curved wall.

**Figure 11.** ESD using a tunneling method. a A large granular laterally spreading tumor (LST) in the rectum. b Distal edge of the tumor after submucosal injection of sodium hyaluronate solution. c Penetration of the tunnel in the sub‐ mucosal layer. d Mucosal defect after the completion of ESD; © Photographs courtesy of H Yamamoto 2010

#### **3.2. Handling of the resected specimen and histopathological assessment**

The resected specimen is carefully retrieved per anally without tearing. A small specimen may be retrieved via suction into the soft hood/cap. A Roth net or other retrieval devices may be used for moderate-sized lesions but with larger lesions, an over-tube may be required. The shape and orientation of the specimen is dutifully recorded, and the specimen pinned out on a Styrofoam or corkboard with the oral and anal sides indicated. The preservation of fresh material is ensured by freezing in liquid nitrogen, embedded in OCT prior to freezing, The slice is cut from the middle without warming up to allow a frozen section to be used for further analysis. We recommend the use of formalin soaked needles to fix the specimen, which should be tension-free as there is 20 to 50% shrinkage of the specimen soaked in formalin.

The ESD specimens are regarded as complex specimens and undergo a standardized process‐ ing during both macroscopic and microscopic assessment of the specimens. They are photo‐ graphed with a styrofoam backing board, with the oral side of the specimen "O" at 12 o'clock position, and the anal side "A" at the 6 o'clock position to ensure that the orientation of the specimens are known. (Fig 12)

**Figure 13.** Mounting of a specimen on a Styrofoam board

ends, it is widened laterally. The mucosa on both sides of the tumour is then incised laterally and dissected submucosally to complete the dissection. (Fig.11). This tunneling technique enables the endoscope tip to be stabilized, hence a more precise control of the Flushknife® is achieved. This technique also enables a good safety margin for further dissection by stretching the submucosal tissue. Adjusting the approach angle of the knife to be tangential to the wall also is easy with this method because an adjusting force with the endoscope tip can be applied in either direction by pushing the mucosa up or pushing the muscle wall down with the tip of the hood (Fig 11b). This method is particularly useful for large lesions, lesions with fibrosis,

**Figure 12.** En bloc resection of the entire lesion (68 × 62 mm in diameter). Histopathologic examination confirmed complete curative resection (adenocarcinoma in adenoma, no invasion to submucosa, no lymphatic or vascular in‐

**Figure 11.** ESD using a tunneling method. a A large granular laterally spreading tumor (LST) in the rectum. b Distal edge of the tumor after submucosal injection of sodium hyaluronate solution. c Penetration of the tunnel in the sub‐ mucosal layer. d Mucosal defect after the completion of ESD; © Photographs courtesy of H Yamamoto 2010

The resected specimen is carefully retrieved per anally without tearing. A small specimen may be retrieved via suction into the soft hood/cap. A Roth net or other retrieval devices may be

**3.2. Handling of the resected specimen and histopathological assessment**

and lesions located on a curved wall.

volvement); © Photographs courtesy of H Yamamoto 2010

110 Colonoscopy and Colorectal Cancer Screening - Future Directions

Since 2009 to 2011, the specimen has been processed as shown below: The principle is to enable a fairly precise assessment of margin involvement. Currently, there are 2 methods of section‐ ing, each having their advantages and disadvantages. The first is described below whereby each transverse section should be submitted separately. The smaller fragments from the lateral edges should be submitted no more than 2 pieces per block. This has been performed since January 2009. The disadvantage of this method is that rounded irregular edges of such specimen are inadvertently shaved off during each 2mm sectioning and these margins cannot be assessed accurately when the sections happen to be tangential to the edge. The second method of sectioning aims to overcome the above problem. The axis of sectioning is perpen‐ dicular to the tangential line drawn at the edge. (Fig 14) This will enable more accurate margin assessment although tissue loss at the apex of each "segment" is inevitable. Inking of the margins is necessary and different colour should be used to represent the respective margins as required.

#### **3.3. Standard operating procedures — Endoscopic Submucosal Dissections (ESD)**

Currently all ESD specimens are regarded as complex specimens by the histopathology laboratory. They are photographed with the styrofoam backing board so that the orientation of the specimen is known. The principle of processing the ESD is to be able to tell the clinician fairly precisely where the margin is involved. An example of how the ESD specimen should be grossed and submitted is given below.

**Figure 14.** Pictorial diagram of how the specimen is sectioned and labeled

Each transverse section is submitted separately and the smaller fragments from the lateral edges should be submitted no more than 2 pieces per block. It is understood that some ESD specimen may have a rather irregular shape. In this situation, the pathologist or assistant trimmer should discuss with the consultant in charge how the specimen should best be processed so that the margins can be mapped back during microscopy.

An example of how the blocking should be represented in the photograph of the specimen is given below. This will be attached to the back of the report and filed. (Fig 14).

The completeness of the ESD is determined through precise histological evaluation. [56] Any intramucosal carcinoma for which the resection margins are free of tumor is considered radically curative. This is also true for cases where there is submucosal invasion that is limited to 1000 *μm* or less, or that the invasive front comprises of only highly or well-differentiated tumor. High risk factors for lymph node metastases are generally absent; hence further surgery is deemed unnecessary. [59]

The clinical course after a smooth and uneventful colorectal ESD is usually favorable. Soft food may be started a day after the treatment, presuming no symptoms, and oral intake is then gradually built up. These patients may be discharged from the hospital within 5 days of the treatment, irrespective of resection size. This is to allow identification of delayed complications such as bleeding or perforation. A few days of bowel rest and intravenous administration of antibiotics are recommended for patients who have had a perforation treated with immediate endoscopic closure; for the patient who complains of abdominal discomfort or develops fever.

**Figure 16.** Example of how the margins can be mapped in correlation with microscopy is given below to enable the

**A13** 

**A3 A4 A5 A6 A7 A8 A9 A10 A11 A12** 

**A1-A2** 

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**A1-A2** 

**A13** 

**A3 A4 A5 A6 A7 A8 A9 A10 A11 A12** 

**Figure 15.** An example of how the trimming should be represented

Involved margin closemargin

clinician to be given appropriate information about the margins of concern.

Surgery is recommended for lesions with a high risk of local recurrence or lymph node metastases as seen in these following circumstances: lesions with 1) positive vertical (deep) margin; 2) those with submucosal invasion >1000 *μm*, 3) presence of vascular infiltration, 4) poorly or undifferentiated cancer front and 5) lesions with budding seen at the deepest part of invasion.

Evolution and Strategy of Endoscopic Treatment for Colorectal Tumours http://dx.doi.org/10.5772/53342 113

**Figure 15.** An example of how the trimming should be represented

**3.3. Standard operating procedures — Endoscopic Submucosal Dissections (ESD)**

be grossed and submitted is given below.

112 Colonoscopy and Colorectal Cancer Screening - Future Directions

A11 A12 A13

A14

is deemed unnecessary. [59]

of invasion.

**Figure 14.** Pictorial diagram of how the specimen is sectioned and labeled

processed so that the margins can be mapped back during microscopy.

given below. This will be attached to the back of the report and filed. (Fig 14).

Currently all ESD specimens are regarded as complex specimens by the histopathology laboratory. They are photographed with the styrofoam backing board so that the orientation of the specimen is known. The principle of processing the ESD is to be able to tell the clinician fairly precisely where the margin is involved. An example of how the ESD specimen should

A1 A2 A3 A4 A5 A6 A7 A8 A9 A10

Each transverse section is submitted separately and the smaller fragments from the lateral edges should be submitted no more than 2 pieces per block. It is understood that some ESD specimen may have a rather irregular shape. In this situation, the pathologist or assistant trimmer should discuss with the consultant in charge how the specimen should best be

An example of how the blocking should be represented in the photograph of the specimen is

The completeness of the ESD is determined through precise histological evaluation. [56] Any intramucosal carcinoma for which the resection margins are free of tumor is considered radically curative. This is also true for cases where there is submucosal invasion that is limited to 1000 *μm* or less, or that the invasive front comprises of only highly or well-differentiated tumor. High risk factors for lymph node metastases are generally absent; hence further surgery

Surgery is recommended for lesions with a high risk of local recurrence or lymph node metastases as seen in these following circumstances: lesions with 1) positive vertical (deep) margin; 2) those with submucosal invasion >1000 *μm*, 3) presence of vascular infiltration, 4) poorly or undifferentiated cancer front and 5) lesions with budding seen at the deepest part

A15 A16 A17

A18

**Figure 16.** Example of how the margins can be mapped in correlation with microscopy is given below to enable the clinician to be given appropriate information about the margins of concern.

The clinical course after a smooth and uneventful colorectal ESD is usually favorable. Soft food may be started a day after the treatment, presuming no symptoms, and oral intake is then gradually built up. These patients may be discharged from the hospital within 5 days of the treatment, irrespective of resection size. This is to allow identification of delayed complications such as bleeding or perforation. A few days of bowel rest and intravenous administration of antibiotics are recommended for patients who have had a perforation treated with immediate endoscopic closure; for the patient who complains of abdominal discomfort or develops fever. Immediate surgical intervention is required for those who develop signs of general peritonitis. Patients who have localized peritonitis should be evaluated with radiologic investigation and clinical assessment, as this may be a result of post polypectomy syndrome. Patients who have had esophageal, gastric, or duodenal ESD, a follow-up endoscopic assessment is performed to check the healing process and identify exposed blood vessels with subsequent therapy. However, no such post-procedural examination is necessary after colorectal ESD, as the risk for delayed bleeding is relatively low. In such cases, patients are discharged from the ward within 1 week without checking ulcer healing. They will need to undergo follow-up endos‐ copies 2 months after the initial ESD to confirm healing and exclude recurrence.

Hemostasis may be more difficult to achieve during the procedure as large elevated lesions, lesions that have been resected before and have developed fibrosis, and carcinomatous lesions develop strong neovascularization. Based on their survey, the authors recommended that to acquire a safe colorectal ESD technique, more than a certain number of cases should be performed. However, this "magic number" was not revealed. More importantly, there was no death occurring during this period of assessment in Japan. Table 3 demonstrates the safety and effectiveness of colorectal ESD and in these reports, ESD was performed or colorectal lesions with a median size of 29-37mm with an average procedure time of 90-120min. Niimi et al reports in a study of 310 consecutive patients who underwent ESD for colorectal epithelial neoplasms, overall survival rates were 97.1% at 3 years and 95.3% at 5 years during a median follow up of 38.7 months (range 12.8-104.2 months). Impressively, the disease specific survival rates were 100% at 3 years, leading the co-author (H.Y) to conclude that in expert hands,

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ESD has emerged as an important therapeutic modality for superficial colorectal tumors, providing a high en bloc resection rate with lower morbidity as compared to surgical ap‐ proaches. Both premalignant and early malignant tumors including depressed lesions and those with fibrosis can now be resected with adequate histological assessment. The nature of this procedure for colorectal lesions, with its inherent difficulties, must be recognized and hence a great degree of both skill and patience is required. Colorectal ESD has a higher risk of complication as compared to gastric or esophageal ESD and consequently, requires both a

thorough knowledge and specific training to achieve satisfactory performance.

colorectal ESD is efficacious and safe.

**Table 3.** Summary of outcomes of colorectal ESD

**4. Conclusion**

In the recent years, various devices and peripheral equipment, as well as newer techniques, have been described by Japanese endoscopists. Colorectal ESD has henceforth become both safer and simpler. The Colorectal ESD Standardization Implementation Working Group in Japan reported the details and results of a nationwide questionnaire survey on the current situation of colorectal ESD in Japan. [61] They analyzed colorectal ESD performed from January 2000 to September 2008 by 194 of the 391 (28.8% of the total number of those institutions that responded). They reported the prevalence of colorectal ESD in Japan, the total number of colorectal ESD procedures performed during the stipulated period and compared it to the number performed in the last 1 year. They also investigated if those endoscopists that perform colorectal ESDs were performing gastric ESD; whether restrictions were placed upon those operators performing the ESD. Technical differences and equipment preferences were also analyzed.

Outcomes analysis was also performed. It was concluded that there was no observed rela‐ tionship between the number of cases performed and the time required to complete an en bloc resection. However, operational difficulty was not documented in these comparisons.

The rate of complete en bloc resection of colorectal ESD for all the institutions was 83.8%. When stratified according to number of cases performed, the rate of complete en bloc resection of the institutions where 100 or more colorectal ESD had been performed was 90.2%; that of institu‐ tions where 50–99 colorectal ESD had been performed was 83.5%; that of those where 25–49 colorectal ESD had been performed was 85.3%; and that of those where 1–24 colorectal ESD had been performed was 82.2%.

Reported overall incidence of perforation as 4.8% from this survey, a value less than 5.9% reported by Tsuda el al in 2006. Reported rates from other series range from 4 to 10%, higher when compared with EMR (0.3 – 0.5%) [36,61-67]. Small perforations recognized during the procedure can be successfully sealed with endoscopic clips. [56,69,70], larger perforations require urgent salvage surgery to prevent peritonitis and its subsequent complications. [71] It can thus be postulated that the safety of colorectal ESD has increased over the recent years.

The overall incidence of hemorrhage was 1.9%. It is the most common complication of EMR and ESD, with rates reported ranging from 1% to 45%, with an average rate of 10% in larger series. [75-77] Most bleeding episodes are observed during the procedure or within the first 24 hours. [71] Delayed bleeding has been reported in up to 13.9% of patients. [72-73]

Hemostasis may be more difficult to achieve during the procedure as large elevated lesions, lesions that have been resected before and have developed fibrosis, and carcinomatous lesions develop strong neovascularization. Based on their survey, the authors recommended that to acquire a safe colorectal ESD technique, more than a certain number of cases should be performed. However, this "magic number" was not revealed. More importantly, there was no death occurring during this period of assessment in Japan. Table 3 demonstrates the safety and effectiveness of colorectal ESD and in these reports, ESD was performed or colorectal lesions with a median size of 29-37mm with an average procedure time of 90-120min. Niimi et al reports in a study of 310 consecutive patients who underwent ESD for colorectal epithelial neoplasms, overall survival rates were 97.1% at 3 years and 95.3% at 5 years during a median follow up of 38.7 months (range 12.8-104.2 months). Impressively, the disease specific survival rates were 100% at 3 years, leading the co-author (H.Y) to conclude that in expert hands, colorectal ESD is efficacious and safe.


**Table 3.** Summary of outcomes of colorectal ESD

### **4. Conclusion**

Immediate surgical intervention is required for those who develop signs of general peritonitis. Patients who have localized peritonitis should be evaluated with radiologic investigation and clinical assessment, as this may be a result of post polypectomy syndrome. Patients who have had esophageal, gastric, or duodenal ESD, a follow-up endoscopic assessment is performed to check the healing process and identify exposed blood vessels with subsequent therapy. However, no such post-procedural examination is necessary after colorectal ESD, as the risk for delayed bleeding is relatively low. In such cases, patients are discharged from the ward within 1 week without checking ulcer healing. They will need to undergo follow-up endos‐

In the recent years, various devices and peripheral equipment, as well as newer techniques, have been described by Japanese endoscopists. Colorectal ESD has henceforth become both safer and simpler. The Colorectal ESD Standardization Implementation Working Group in Japan reported the details and results of a nationwide questionnaire survey on the current situation of colorectal ESD in Japan. [61] They analyzed colorectal ESD performed from January 2000 to September 2008 by 194 of the 391 (28.8% of the total number of those institutions that responded). They reported the prevalence of colorectal ESD in Japan, the total number of colorectal ESD procedures performed during the stipulated period and compared it to the number performed in the last 1 year. They also investigated if those endoscopists that perform colorectal ESDs were performing gastric ESD; whether restrictions were placed upon those operators performing the ESD. Technical differences and equipment preferences were also

Outcomes analysis was also performed. It was concluded that there was no observed rela‐ tionship between the number of cases performed and the time required to complete an en bloc resection. However, operational difficulty was not documented in these comparisons.

The rate of complete en bloc resection of colorectal ESD for all the institutions was 83.8%. When stratified according to number of cases performed, the rate of complete en bloc resection of the institutions where 100 or more colorectal ESD had been performed was 90.2%; that of institu‐ tions where 50–99 colorectal ESD had been performed was 83.5%; that of those where 25–49 colorectal ESD had been performed was 85.3%; and that of those where 1–24 colorectal ESD

Reported overall incidence of perforation as 4.8% from this survey, a value less than 5.9% reported by Tsuda el al in 2006. Reported rates from other series range from 4 to 10%, higher when compared with EMR (0.3 – 0.5%) [36,61-67]. Small perforations recognized during the procedure can be successfully sealed with endoscopic clips. [56,69,70], larger perforations require urgent salvage surgery to prevent peritonitis and its subsequent complications. [71] It can thus be postulated that the safety of colorectal ESD has increased over the recent years.

The overall incidence of hemorrhage was 1.9%. It is the most common complication of EMR and ESD, with rates reported ranging from 1% to 45%, with an average rate of 10% in larger series. [75-77] Most bleeding episodes are observed during the procedure or within the first

24 hours. [71] Delayed bleeding has been reported in up to 13.9% of patients. [72-73]

copies 2 months after the initial ESD to confirm healing and exclude recurrence.

114 Colonoscopy and Colorectal Cancer Screening - Future Directions

analyzed.

had been performed was 82.2%.

ESD has emerged as an important therapeutic modality for superficial colorectal tumors, providing a high en bloc resection rate with lower morbidity as compared to surgical ap‐ proaches. Both premalignant and early malignant tumors including depressed lesions and those with fibrosis can now be resected with adequate histological assessment. The nature of this procedure for colorectal lesions, with its inherent difficulties, must be recognized and hence a great degree of both skill and patience is required. Colorectal ESD has a higher risk of complication as compared to gastric or esophageal ESD and consequently, requires both a thorough knowledge and specific training to achieve satisfactory performance.

### **Acknowledgements**

Dr Cheng Chee Leong & A/Prof Teh Ming. Department of Pathology, National University Hospital, Singapore

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