Long-term outcomes of endoscopic submucosal dissection for undifferentiated type early gastric cancer over 2 cm with R0 resection

BACKGROUND Endoscopic submucosal dissection(ESD)for over 2 cm in size undifferentiated type(UD type)early gastric cancer(EGC)confined to the mucosa is not only challenging,but also long-term outcomes are not well known.AIM To evaluate the long-term outcomes of ESD done for UD type EGCs confined to the mucosa over 2 cm in size and compare the results with those where the lesions were less than 2 cm.METHODS 143 patients with UD type EGC confirmed on histology after ESD at a tertiary hospital were reviewed.Cases with synchronous and metachronous lesions and a case with emergency surgery after ESD were excluded.A total of 137 cases were enrolled.79 cases who underwent R0 resection were divided into 2 cm or less(group A)and over 2 cm(group B)in size.RESULTS Among 79 patients who underwent R0 resection,the number in group A and B were 51 and 28,respectively.The mean follow-up period(SD)was 79.71±45.42 months.There was a local recurrence in group A(1/51,2%)and group B(1/28,3.6%)respectively.This patient in group A underwent surgery while the patient in group B underwent repeated ESD with no further recurrences in both patients.There was no regional lymph node metastasis,distant metastasis,and deaths in both groups.With R0 resection strategy for ESD on lesions over 2 cm,20.4%(28/137)of patients were able to avoid surgery compared with expanded indication.CONCLUSION If R0 resection is achieved by ESD,UD type EGCs over 2 cm also showed good and similar clinical outcomes as compared to lesions less than 2 cm when followed for over 5 years.With R0 resection strategy,several patients can avoid surgery.