Expanded Indication of Endoscopic Submucosal Dissection (ESD) for Early Gastric Cancer (GC)-Clinical Outcomes of a Prospective Study-

Abstract

Background: Endoscopic mucosal resection (EMR) is recognized as a minimally invasive treatment for superficial GC without metastasis. ESD is a promising technique to obtain en bloc specimen even for large and/or ulcerative lesions. The aim of this study was to assess efficacy and safety of ESD for GC out of the supposed conditions without nodal metastasis, as shown in Japanese guideline of treatment for GC. Patients and Methods: We designed a prospective study in which ESD was applied to patients with differentiated-type GC with no definite signs of submucosal invasion up to 30 mm in diameter regardless of ulceration or above 30 mm without ulceration. Based on pathological findings after the ESD, patients were devided into two groups. In one, they were followed up under the conjecture of no metastasis. In the other, they were advised to receive additional surgical resection due to the risk of metastasis. The conditions supposed to have no metastasis were differentiated-type mucosal GC above 30 mm in diameter without ulceration and GC up to 30 mm with ulceration or minute submucosal invasion. The protocol was approved by the ethics committee of Osaka National Hospital, and consent to take part in the study was obtained from patients. Complete resection was defined if the lateral and vertical margins were free of tumor pathologically. Followed-up endoscopic examinations were performed 1, 3, 6 months later, and then every six months. Results: Between Nov. 2001 and Nov. 2005, 251 patients were enrolled. The average size of GC resected was 22 mm (range: 2-70 mm). Complete resection was achieved in 87%. No emergent surgery and no immediate mortality was noted. Perforation and bleeding were encountered in 8% and 9%, respectively. Bleeding happened more frequently in case of GC with ulceration (p < 0.05). Forty-two patients were recommended to receive additional operation mainly because of massive submucosal invasion or lymphovascular involvement, and nodal metastasis was recognized in 3 of 12 patients who were actually operated on. Among the remaining 209 followed-up patients, 3 (1.5%) recurred locally during follow-up period of median 18 mos (range: 2-36), and they were successfully treated by repeated ESD. No distant metastasis was noted in the follow-up period. Conclusions: ESD achieves complete resection of mucosal GC regardless of size or ulceration, providing the precise histological assessment. But it is associated with a higher risk of bleeding and perforation compared with conventional EMR. Further, the long-term prognosis should be investigated.