ESD

Fig. 7.1

(a) Schema and endoscopic view of ESD with DFC, involving an approach from the straight endoscopic position. In the lesions located in the anterior wall of the gastric antrum, the oral side of the resected mucosa is elevated by pulling the dental floss out through the mouth. (b) Schema and endoscopic view of ESD with DFC, involving an approach from the retroflexed endoscopic position. In lesions located in the lesser curvature of the gastric corpus, the anal side of the resected mucosa is elevated by pulling the dental floss out through the mouth. (c) Preparation of the DFC. A long piece of dental floss is tied to the arm of the hemoclip, and then the hemoclip tied with the dental floss is withdrawn into the transparent hood and the accessory channel of the endoscope to enable the insertion of the endoscope

../images/442926_1_En_7_Chapter/442926_1_En_7_Fig2_HTML.png — Fig. 7.2

(a) ITknife2 (KD-611L, Olympus Medical Systems). (b) HookKnife (KD-620LR, Olympus Medical Systems). (c) DualKnife (KD-650L, Olympus Medical Systems). (d) FlashKnife BT (Fujifilm Medical Co., Ltd.). (e) SafeKnife (DK2518DV1, Fujifilm Medical Co., Ltd.). (f) Clutch Cutter (DP2618DT-50-, Fujifilm Medical Co., Ltd.)

../images/442926_1_En_7_Chapter/442926_1_En_7_Fig3_HTML.jpg — Fig. 7.3

(a) Mucosal cutting by Clutch Cutter surrounding marking dots after submucosal injection. (b) Submucosal dissection using Clutch Cutter. (c) Endoscopic hemostasis for small vessels by using Clutch Cutter

Device Settings

Clutch Cutter used for gastric ESD has a 0.4 mm-wide and 5 mm-long serrated cutting edge well suited for grasping function. The outer side of the forceps is insulated so that electrosurgical current energy is concentrated at the inner closed edge of the blade. Forced coagulation mode (VIO 300D, Erbe, Tübingen, Germany; 30 W, effect 3) is used for marking, ENDO CUT Q mode (effect 1, duration 3, interval 1) is used for mucosal incision and submucosal dissection, and soft coagulation mode (100 W, effect 5) is recommended for hemostatic treatment .

A soft transparent hood (JMDN 38819001, Top Corp., Tokyo, Japan) or a small-caliber-tip transparent hood (ST hood, Fujifilm Medical Co., Ltd.) is sometimes useful to stabilize the operating field and to create countertraction for exfoliating the submucosal tissue [28].

Mucosal Cutting

Figure 7.4a shows an EGC 2 cm in size on the posterior wall of the upper corpus of the stomach. Mucosal incision is smoothly carried out on the peripheral side of the marking dots after submucosal injection with normal saline with indigo carmine dye. The Clutch Cutter is rotatable to the desired orientation (Fig. 7.4b, c). Indigo carmine is added to the submucosal injection fluid in order to better identify the blue-colored submucosal layer (with any injection needle available). Sodium hyaluronate (MucoUp, Boston Scientific, Tokyo, Japan) is also often used because of longer-lasting submucosal cushion in order to prevent perforation [29].

../images/442926_1_En_7_Chapter/442926_1_En_7_Fig4_HTML.png — Fig. 7.4

(a) A shallow depressed lesion on the posterior wall of the corpus. (b) Marking dots by the Clutch Cutter with forced coag (50 W) 5 mm outside the lesion. (c) Mucosal incision using Clutch Cutter scissors allows easy incision with the rotatable device with enough grasping. (d) Hemoclip – tied by a dental floss – as an anchor for traction. (e) Visualized and safe dissection of submucosal layer using Clutch Cutter by ENDO CUT Q mode under good visualization and tension of the submucosa. (f) Resected material pinned on the board

Submucosal Dissection

After completing the circumferential cutting, the submucosal layer underneath the lesion is directly dissected. At this step, the traction method is very useful and makes dissection easy, safe, and rapid because of good visualization (Fig. 7.4d). The hemoclip – tied by a dental floss – is anchored to a suitable site of the lesion for oral traction. The clip varies according to the location of the lesion. For lesions approached from the retroflexed endoscopy position, the clip is anchored at the anal side edge of the resected mucosa. In lesions approached from the straight endoscopy position, the clip is anchored at the oral side edge of the resected mucosa. During submucosal dissection, the anchored suture material located outside of the patient is pulled to the oral side with gentle manual traction by the operator or an assistant. Good visualization and tension of the submucosa are obtained by the resected mucosa that is turned over (Fig. 7.4e).

When a small artery and/or vein is encountered in the submucosal layer, the Clutch Cutter can first control the vessel with soft coagulation mode and after that cut it with ENDO CUT Q mode . However, do not hesitate to change Clutch Cutter to Coagrasper G (Olympus Medical Systems) which is more effective to grasp the bleeding vessel and control it.

Preparation for Pathological Staging

The importance of meticulous pathological staging after endoscopic resection cannot be overemphasized. Accurate staging can only be achieved when the specimen is properly oriented by the endoscopist or their assistant immediately after excision in the endoscopy unit prior to be immersed in formaldehyde.

Orientation of the specimen is best performed by fixing its periphery with thin needles inserted into an underlying plate of rubber or wood (Fig. 7.4f). The submucosal side of the specimen is placed in contact with the plate. After fixation, the specimen is sectioned serially at 2 mm intervals parallel to a line that includes the closest resection margin of the specimen so that both lateral and vertical margins are assessed. The depth of tumor invasion (T) is then evaluated along with the degree of differentiation and lymphovascular invasion, if any. The report must include histological type, tumor depth, size, location, and macroscopic appearance. The presence of ulceration and lymphatic and/or venous invasion and the status of the margins of resection should be reported in detail to determine the curability.

Surveillance After Gastric ESD

According to the Japanese guidelines, the curability after ESD/EMR for EGC is classified into three groups: curative resection, curative resection for expanded indication, and non-curative resection (Fig. 7.5) [30–34]. En bloc resection with no lymphovascular invasion and a negative surgical margin are required for curative resection or that for expanded indication. No additional treatment is needed in patients with curative resection.

../images/442926_1_En_7_Chapter/442926_1_En_7_Fig5_HTML.png — Fig. 7.5

The therapeutic flowchart after gastric ESD/EMR in the Japanese guidelines

According to the European guidelines (European Society of Gastrointestinal Endoscopy, ESGE) [35], additional treatment is also not necessary after curative resection , which is the same as in the Japanese guidelines. In the USA, the National Comprehensive Cancer Network guidelines (NCCN guidelines) regard EMR or ESD as having the potential of being therapeutic and one of the treatment options for Tis or T1a cancer ≤2 cm [36].

After gastric ESD, attention should be focused on the development of metachronous gastric cancers. The 5-year and 10-year cumulative incidences were 9.5% and 22.7%, respectively [37]. Almost all secondary gastric cancers were treatable by ESD by the scheduled endoscopic surveillance (6–12 months) [38]. The Japanese guidelines also recommend endoscopic surveillance at intervals of 6–12 months, whereas ESGE and NCCN guidelines recommend annual endoscopy from 1 year after ESD/EMR. Thus, when complete resection could be achieved for the initial EGC, the following endoscopic surveillance is recommended after ESD/EMR (Fig. 7.6).

../images/442926_1_En_7_Chapter/442926_1_En_7_Fig6_HTML.png — Fig. 7.6

The flowchart of follow-up after gastric ESD/EMR

When the histopathological findings meet the expanded criteria, no additional treatment is needed in the Japanese guidelines (Fig. 7.5). Recently, a multicenter retrospective analysis in Japan clarified that 0.14% (6/4202) of such patients had metastatic recurrence during the median follow-up duration of 56 months after ESD [39]. Surveillance for metastatic recurrence as well as metachronous gastric cancer is recommended, although the risk of the former is very small. In addition to endoscopic surveillance at every 6 months in the first year and at intervals of (6–)12 months for at least 10 years after ESD/EMR, follow-up with computed tomography (CT) (or ultrasonography) is desirable at intervals of 6–12 months. Hence, patients should be explained that they have a negligible but not zero risk of metastatic recurrence after gastric ESD/ESD.

It is controversial whether the expanded criteria are applicable for European patients. For differentiated-type EGC, the ESGE recommends ESD for EGCs that meet the expanded criteria, whereas ESMO and the German Society of Gastroenterology give restrictive recommendations [40, 41], which recommend gastrectomy for cases meeting the expanded criteria. Regarding undifferentiated-type EGC, the ESGE guidelines regard ESD for the expanded criteria as an option. In such patients, the ESGE guidelines recommend that gastrectomy is always considered with the decision made on an individual basis. There has been no report about the expanded criteria for gastric ESD/EMR in USA. As described previously, the NCCN guidelines regard EMR or ESD as one of the treatment options only for Tis or T1a cancer ≤2 cm. However, a report based on the Surveillance, Epidemiology, and End Results (SEER) database of the USA suggests the existence of different biological aggressiveness in T1a gastric cancer among racial/ethnic groups [42].

When the lesion does not meet the curative criteria , the ESD is regarded as non-curative resection. In cases of differentiated-type EGC with the only unsatisfactory curative factor of piecemeal resection or resection en bloc with a positive horizontal margin, surgical resection is not the only option because such cases have a very low risk of harboring LNM. Repeated ESD, endoscopic coagulation using a laser or argon plasma coagulator, or close observation expecting a burn effect of the initial endoscopic resection could be proposed as an alternative in such cases, with the patient’s informed consent.

In the other type of non-curative resection, additional gastrectomy with lymph node dissection is recommended in the ESGE and Japanese guidelines because such lesions have the potential for LNM. When gastric ESD/EMR is performed, 17–29% of the patients do not meet the curative criteria. However, LNM is found in only 5–10% of patients with such lesions [43]. In the clinical setting, nearly half of such patients are followed up with no additional treatment after ESD in Japan, due to the age, underlying disease, and patients’ preference. Also, in Germany, 69% (27/39) of such patients were followed up with no additional treatment after non-curative resection for EGC [44].

A randomized controlled trial clarified that prophylactic eradication of Helicobacter pylori after ESD/EMR for EGC reduced the risk of metachronous gastric cancer to about one-third [45]. However, some studies including one randomized controlled trial revealed conflicting results [46]. Although eradication therapy is recommended in Helicobacter pylori-infected patients, further investigation about this issue is needed.

Future Perspective

Patients who are stratified to have no or lower risk of LNM than the risk of mortality from surgery are ideal candidates for endoscopic resection [47, 48]. Endoscopic resection allows complete pathological staging of the cancer, which is critical for determining potential for metastasis [49]. The optimal staging method of EGC is to evaluate the pathology of en bloc resected material [50, 51].

In cancer treatment, completely curing the illness is extremely important. However, if quality of life (QOL) is impaired by procedures that are superior only in terms of reducing marginal risks, patients may have difficulties in daily life and social rehabilitation after treatment [52, 53]. The stomach not only serves as a storage compartment but also plays a role in external secretion for digestion and absorption as well as in internal secretion. Therefore, if there is no difference of curability among different treatment methods, long-term QOL should be considered seriously when we select a treatment method, especially in elderly patients [48].

Recently, a simple risk-scoring system, named eCura system , was established for stratifying the risk of LNM in such patients (Fig. 7.7) [54]. This is a seven-point scoring system with three risk categories based on five clinicopathological factors in order to predict LNM. In this system, 3 points are assigned for positive lymphatic invasion, and 1 point is assigned for tumor size of >30 mm, SM2 invasion, positive venous invasion, and positive vertical margin. The rate of LNM in the low- (0–1 point), intermediate- (2–4 points), and high-risk (5–7 points) categories was 2.5%, 6.7%, and 22.7%, respectively. In addition, when the patients were followed up with no additional treatment after non-curative resection for EGC, 5-year cancer-specific survival (CSS) in each risk category was 99.6%, 96.1%, and 90.1%, respectively. A Japanese multicenter evaluation of laparoscopic gastrectomy (mainly distal gastrectomy) for EGC reported 5-year CSS rates of 99.8% for stage T1a disease and 98.7% for stage T1b disease [55]. Thus, although radical surgery is the standard therapy for patients with non-curative resection for EGC, the eCura system provides useful information for deciding the treatment strategy after non-curative resection for EGC, especially in elderly patients and/or those with severe comorbidities.