We retrospectively reviewed the records of post distal gastrectomy patients with gastric remnant cancer, who underwent distal gastrectomy for the treatment of gastric cancer, admitted to Sumitomo Besshi Hospital and Shikoku Cancer Center between January 1998 and December 2007. Patients admitted during this period were divided into a conventional endoscopic mucosal resection (EMR) group and into a IT-ESD group according to the endoscopic resection method. Since 2000, the IT-knife procedure has been used instead of the conventional EMR for the treatment of gastric remnant cancer. Patient backgrounds, the one-piece resection rate, complete resection (CR) rate, operation times, bleeding rate, and perforation rate were compared between the groups. Patients with severe underlying disease, such as heart disease, respiratory disease, liver disease, or bleeding tendency, were excluded from the indication of ESD in our institute; however, no patients had severe underlying disease in this study. Patients taking drugs to promote bleeding, such as ticlopidine, aspirin, or warfarin, underwent ESD after a fixed term of drug discontinuance. All patients fulfilled the following criteria in this study: diagnosed as having mucosal gastric carcinoma by endoscopic findings or endoscopic ultrasonography, a biopsy specimen obtained from the lesion revealed differentiated adenocarcinoma, without ulceration of the lesion, no residual/local recurrence lesion after endoscopic treatment and the diameter of the lesion was up to 30 mm. The performance status (PS) of each patient was less than 2 on the Eastern Cooperative Oncology Group (ECOG) scale. IT-ESD was performed under informed consent. Two highly skilled endoscopists familiar with EMR and ESD performed endoscopic resection in this study.

Conventional EMR was performed with a 2-channel endoscope[1618]. The mucosa around the lesion was marked with coagulation current, and saline containing 0.0025% epinephrine was injected until the mucosa around or under the lesion was raised. Grasping forceps was passed through the loop of the conventional polypectomy snare, and an area near the lesion was grasped with the forceps to elevate the lesion. Then the snare was opened and the lesion was strangled. The specimen was completely resected by electric current application.

IT-knife was developed by Hosokawa and Yoshida in 1994 in Japan[19]. IT-knife has a ceramic ball at the top of the incising needle knife[111219–21] to prevent perforation of the gastric wall. IT-ESD was performed as previously described using a single-channel endoscope[312141722]. Marks were made at several points along the outline of the lesion with a coagulation current, and saline containing 0.0025% epinephrine was injected just outside the marks to prevent perforation until the mucosa around the lesion was raised. A circumferential incision in the mucosa just outside the marks was made using an IT-knife, with a safe lateral margin, and the submucosal tissue under the circumcised area was abraded with it. The specimen was then either completely resected using the IT-knife, or finally removed using a conventional polypectomy snare if it was attached only to a pedicle (Figure 1).

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Figure 1 The procedure of endoscopic submucosal dissection using an insulation-tipped diathermic knife (IT-ESD). A: A IIc lesion (black arrows) is seen near the suture line (white arrow) in the remnant stomach; B: Completion of IT-knife cutting around the lesion with a safe lateral margin; C: Abrasion of the submucosal tissue under the circumcised area with IT-knife (white arrow); D: the tumor is completely resected with IT-knife.

A gastrointestinal pathologist evaluated the ESD specimens with special attention to the depth of tumor invasion, and the lateral and deep margins of the excision. Resected specimens were cut into 2 mm slices according to the Japanese Classification of Gastric Carcinoma[23] and evaluated as to whether cancerous glands were present or absent at the margin of each slice.

When one-piece resection could be performed, it was easy to evaluate the completeness of the resection histologically. The efficacy of resection was determined according to the completeness of the resection: when the tumor was resected as a single piece, contained within the mucosal layer, and when the margin was definitely free of tumorous glands, resection was considered to be complete. Multifragment resections were defined as incomplete when tumorous glands were present in 2 or more fragments histologically, even if endoscopically the lesion had been completely removed. If the lateral margin of the lesion could not be evaluated histologically because of the effects of the electrosurgical current or mechanical damage, the resection was defined as being incomplete.

Bleeding and perforation were two major complications of ESD. Bleeding (delayed bleeding) was defined as clinical evidence of bleeding as hematemesis or melena at 1 d-10 d after ESD and requiring endoscopic treatment.

Values are expressed as the mean ± SD. Statistical analysis was performed using the unpaired Student’s t-test and the chi-square test. A P value of < 0.05 was considered significant.

Concerning tumor location and gross type, no significant differences were found between patients included in the EMR (n = 15) and those included in the IT-ESD (n = 17) group (Tables 1 and 2, and Figure 2).

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Figure 2 Clinical courses after endo-scopic submucosal dissection (ESD) and conventional endoscopic mucosal resection (EMR) for remnant gastric cancers.

The mean age was 68.3 ± 9.2 years (range, 46-80 years) in the EMR and 73.1 ± 5.4 years (range, 64-84 years) in the IT-ESD group. The mean size of the lesion was 12.7 ± 2.9 mm and 15.5 ± 5.6 mm in the in the EMR and the IT-ESD group, respectively, with no significant difference between the two groups. No significant differences were found in the rate of underlying cardiopulmonary disease between the two groups [2 patients (13%) in the EMR group and 2 patients (12%) in the IT-ESD group] nor in the number of patients receiving anticoagulant therapy [one patient (6.7%) in the EMR group vs one patient (5.9%) in the IT-ESD group].

There was no significant difference in the one-piece resection rate among the groups (73% in the EMR group vs 100% in the IT-ESD group). The CR rate was significantly higher in the ESD group (40% in the EMR group vs 82% in the IT-ESD group). The mean operation time was 21.1 min ± 12.2 min for the EMR group and 57.6 min ± 31.9 min for the IT-ESD group. There were 4 cases of bleeding after endoscopic resection: one (6.7%) in the EMR group and 3 (18%) in the IT-ESD group, but no patient needed further surgery. All 3 patients with delayed bleeding developed clinical signs of hematemesis or melena 1 or 2 d after ESD. No patient developed hematemesis or melena later than 3 d after ESD. There was no severe delayed bleeding with a need for transfusion. Perforation occurred in none of the patients. Twelve patients were judged as having incomplete resection in both groups. The margin of the fragment was positive for tumor or the lateral margin of the lesion could not be evaluated because of the effects of the electrosurgical current in 5 patients (four in the EMR group and one in the IT-ESD group). These five patients did not undergo additional laser or surgical therapy, although they have remained under close periodic observation. Three patients (one in the EMR group and two in the IT-ESD group) were judged as having submucosal invasion and two underwent total gastrectomy of the remnant stomach with regional lymph nodes dissection (additional surgery). The remaining case (in the EMR group) refused surgery and has been under close periodic observation. A total of 30 patients who did not undergo additional surgery were followed by endoscopy in both groups at least every year after treatment. The mean follow-up period was 2135 d (range 180-3285 d). There were no local recurrences after CR in the 20 patients in both groups and one patient resulting in incomplete resection in the IT-ESD group during that period. Only one patient in the EMR group resulted in piece-meal resection had a local recurrence 2 years after EMR and underwent additional EMR therapy.

Endoscopic submucosal dissection (ESD) is a useful new endoscopic mucosal resection (EMR) method, which has recently become widespread in Japan due to its high one-piece resection rates. Gastric cancer of the proximal gastric remnant is now increasing in Japan. The aim of this study was to evaluate the effectiveness of ESD using an insulation-tipped diathermic knife (IT-ESD) for the treatment of patients with gastric remnant cancer post distal gastrectomy.

It is still uncertain whether conventional EMR or IT-ESD results in better clinical outcome in the treatment of gastric remnant cancer post distal gastrectomy. Further investigations on a larger scale to compare the efficacy and safety of conventional EMR vs IT-ESD should be conducted.

In this article we analyze if IT-ESD is superior to conventional EMR in the complete resection rate in 32 patients with gastric remnant cancer post distal gastrectomy.

This study serves as a reminder to readers of the management of mucosal remnant gastric cancer post distal gastrectomy with IT-ESD. Because of its high complete resection rate, IT-ESD may be worth trying as the first therapy for treating patients with mucosal remnant gastric cancer post distal gastrectomy.

It is an interesting initial series comparing conventional EMR to IT-ESD in the treatment of gastric remnant cancer post distal gastrectomy. The study presents novel findings.