Seiichiro Abe

Indications and Techniques for Endoscopic Submucosal Dissection

Endoscopic submucosal dissection (ESD) allows for curative resection of superficial neoplasms of the gastrointestinal tract. Although ESD is the standard of care in Japan, its adoption in the West has been slow. Recent studies have shown the advantages of ESD over endoscopic mucosal resection, and as many of the barriers to ESD have been overcome, we are seeing an increasing interest in this technique. ESD can be used to treat superficial gastric, esophageal, and colorectal lesions. The most important pre-procedure step is estimating the depth of invasion of a lesion and by proxy the risk of lymph node metastasis. After a lesion has been resected, the histopathological analysis will determine whether the resection was curative or whether further surgery is needed. In conclusion, ESD is being more widely used in the West, and it is important to understand the indications, limitations, and techniques of ESD.

A pilot study of fluorescent imaging of colorectal tumors using a γ-glutamyl-transpeptidase-activatable fluorescent probe.

Backgrounds/Aim: Colorectal laterally spreading tumors (LSTs) are sometimes difficult to visualize even with image-enhanced endoscopy. γ-Glutamyl-transpeptidase (GGT) is a cell surface-associated enzyme that is overexpressed in various types of human cancers. Furthermore, GGT expression is higher in colorectal cancer cells than in normal colorectal mucosa. γ-Glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), an activatable fluorescent probe, is nonfluorescent under a neutral pH and normal cellular environment; however, it turns highly fluorescent upon reaction with GGT. We evaluated ex vivo fluorescent imaging of colorectal LSTs using this GGT-activatable fluorescent probe. Methods: Between March 2013 and March 2014, 30 endoscopically resected colorectal LSTs were prospectively included in this study. Each was analyzed by first taking a baseline image before spraying, then spraying with gGlu-HMRG onto the freshly resected specimen, and finally taking fluorescent images 15 min after spraying with a dedicated imaging machine. Results: Of the LSTs, 67% rapidly showed positive fluorescent activity. These activities were shown in adenoma (54%) and carcinoma in adenoma (76%), and in LST-granular type (80%) and LST-nongranular type (40%). Conclusion: Topically spraying gGlu-HMRG enabled rapid and selective fluorescent imaging of colorectal tumors owing to the upregulated GGT activity in cancer cells.

Video-based supervision for training of endoscopic submucosal dissection

BACKGROUND AND STUDY AIM Adoption of endoscopic submucosal dissection (ESD) in Western countries has been limited by the difficulty in learning the procedure. Although a porcine model is commonly used for ESD training, without expert guidance the procedure is difficult to master. The availability of Western ESD experts is limited, and expert supervision through a remote video-based system may be a practical method for Western endoscopists to learn ESD. The aim of this study was to assess the value of video-based remote evaluation in supervising ESD training. METHODS Two Western endoscopists performed ESD training procedures in an ex vivo porcine model at least every 2 weeks until competency was achieved. Competency was defined as consistent en bloc resection of a 3-cm area within 30 minutes, and without perforation, using the proper ESD technique. A Japanese ESD expert at the National Cancer Center in Tokyo, Japan, analyzed the training videos, scored them, and provided written feedback for improvement after each training session and before the trainees next training session. RESULTS Endoscopist 1 reached competency at 23 procedures and endoscopist 2 reached competency at 25 procedures. No difference in skill improvement between the two endoscopists was noted. One trainee subsequently completed eight ESD procedures in patients, with curative en bloc resection and no complications. CONCLUSION A standardized ESD training program including educational presentations/videos and preclinical animal training with expert guidance through a remote video-based system is an effective tool for learning ESD techniques in preparation for performing the procedure in humans.

A Retrospective Study of 5-year Outcomes of Radiotherapy for Gastric Mucosa-associated Lymphoid Tissue Lymphoma Refractory to Helicobacter pylori Eradication Therapy

BACKGROUND The favorable response rate of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication has been demonstrated. However, there are limited data available on the long-term outcomes. The aim of this retrospective study was to evaluate the long-term outcomes of radiotherapy for localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication. METHODS Thirty-four consecutive patients with localized gastric mucosa-associated lymphoid tissue lymphoma that were refractory to eradication were treated with radiotherapy (a total dose of 30 Gy). The response and adverse events of radiotherapy were retrospectively analyzed as short-term outcomes, and recurrence-free, overall and disease-specific survival rates were calculated as long-term outcomes. RESULTS Thirty-three (97.1%) patients achieved complete remission and radiotherapy was well tolerated. One patient underwent emergency gastrectomy due to severe hematemesis. Of the 34 patients during the median follow-up period of 7.5 (1.2-13.0) years, one patient had local recurrence after 8.8 years, one patient underwent surgery for bowel obstruction secondary to small bowel metastasis after 5.1 years and one patient had pulmonary metastasis after 10.9 years. Pathologically, all three recurrences revealed mucosa-associated lymphoid tissue lymphoma without any transformation to high-grade lymphoma. None died of gastric mucosa-associated lymphoid tissue lymphoma. The 5-year recurrence-free survival rate was 97.0%. The 5-year overall survival rates and disease-specific survival rates were 97.0 and 100%, respectively. CONCLUSIONS Radiotherapy in patients with localized gastric mucosa-associated lymphoid tissue lymphoma refractory to Helicobacter pylori eradication can achieve excellent overall survival. However, long-term surveillance is necessary to identify late recurrences.

Efficacy and Feasibility of Combination Chemotherapy with S-1 and Cisplatin (2 Weeks Regimen) for Advanced Gastric Cancer

OBJECTIVE Although combination chemotherapy with 3 weeks of S-1 and cisplatin is effective for advanced gastric cancer, the toxicities of S-1 which mostly occur during the third week of administration are a major problem. To achieve fewer adverse effects with S-1 and higher dose intensity of cisplatin, we performed combination chemotherapy with 2 weeks of S-1 and cisplatin as first line. The aim of this retrospective study was to analyse the efficacy and feasibility of this regimen. METHODS S-1 (40-60 mg depending on patients body surface area) was given orally twice daily for 2 consecutive weeks, and 70 mg/m(2) cisplatin was given intravenously on day 8, followed by a 2-week rest period. RESULTS Forty-eight patients received a total of 184 courses of chemotherapy. Overall response rate was 40.6% and median survival time was 411 days. Dose intensities were 257.6 mg/m(2)/week for S-1 and 16.4 mg/m(2)/week for cisplatin. The incidences of grade 3/4 haematological toxicities were leucopenia (19%), neutropenia (29%) and anaemia (17%), and those of grade 3 non-haematological toxicities were anorexia (31%) and nausea (21%). The rate of treatment discontinuation owing to toxicity was 10%. CONCLUSIONS This regimen may be effective as an alternative therapy to 3 weeks of S-1 and cisplatin to reduce the toxicity of chemotherapy for advanced gastric cancer.