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

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. 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. 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 +/- A 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. 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.