Ishioka M, Yoshio T, Miyamoto Y, et al. - Following endoscopic submucosal dissection (ESD) for undifferentiated-type cancer, researchers assessed the incidence and characteristics of metachronous cancer. Researchers enrolled 175 patients who had undergone ESD for undifferentiated-type early gastric cancer and 350 patients who undergone ESD for differentiated-type early gastric cancer  (median observation period was 6.0 years and 5.4 years, respectively). All patients then had a follow-up esophagogastroduodenoscopy annually. The data indicated that, in this cohort, metachronous cancers developed only in H pylori-infected patients. The curative resection rate of ESD was significantly decreased, although the incidence of metachronous cancers was significantly lower in patients after ESD for undifferentiated-type cancer. After ESD, routine surveillance should be conducted more carefully for undifferentiated-type cancer, particularly in H pylori-infected patients.