Endoscopic submucosal dissection for early gastric cancer with undifferentiated histology: Could we extend the criteria beyond?

Background: Endoscopic submucosal desection (ESD) is an effective treatment for selected patients with early gastric cancer (EGC). The purpose of this study was to examine the short-term and long-term outcomes of ESD of undifferentiated early gastric cancer. Methods: Data for 1,241 patients who underwent ESD for treatment of EGC between February 2003 and May 2010 were collected. We performed a retrospective analysis of the medical records of 74 patients diagnosed with undifferentiated EGC. We divided the enrolled cases into two groups: the expanded-criteria group (EC group) versus the non-EC group, according to lesion size, presence of ulceration, and pathologic review. Results: Of a total of 74 lesions with undifferentiated EGC, as a result of pathologic examination the EC group included 29 cases and the non-EC group included 45 cases. The mean diameter of lesions was 19.86 ± 12.5 mm. The overall rates of en bloc resection and complete resection were 90.5 % (67/74) and 73 % (54/74), respectively. The curative resection rate was low at 31.1 %. If limited to the pathologically diagnosed EC group, the curative resection rate was 79.3 % (23/29). During median follow-up periods of 34 months (range 7-81), local recurrences were observed in 5.5 % (4/74) of patients. All of these were in the non-EC group and all underwent noncurative resection. There was no mortality related to ESD for treatment of EGC during follow-up. Conclusions: ESD may be a feasible treatment for selected patients with undifferentiated EGC; this should be validated by development of new criteria for ESD for treatment of EGC.