Background: Endoscopic submucosal dissection (ESD) has been widely performed for the treatment of early gastric cancer (EGC). The aim of this study is to examine the effectiveness of ESD in submucosal invasive gastric cancers (SM-GC), with a special focus on patients who underwent non-curative resection.
Methods: Data for 1,246 patients who underwent ESD for treatment of EGC at six medical centers in Daegu-Gyeongbuk, Korea, between February 2003 and May 2010 were collected. After retrospective analysis of ESD databases, 118 patients were enrolled and classified into three groups: (1) EGC with submucosal invasion less than 500 μm (SM1-GC) that met the expanded criteria (EC) (SM1 EC, n = 42); (2) SM1-GC that did not meet the EC (SM1 non-EC, n = 38); and (3) EGC with submucosal invasion greater than 500 μm (SM2-GC, n = 38).
Results: The en bloc and complete resection rates did not differ significantly among the three groups. However, the curative resection rate was significantly better in the SM1 EC group (69.0%) compared to that in SM1 non-EC and SM2-GC groups (0% in both cases). Out of a total of 118 patients, 89 (75.4%) underwent non-curative resection, and cancer recurrence was observed in 9 (9/89, 10.1%). We analyzed the survival rate in these non-curative patients and the overall survival and disease-free survival did not differ significantly between patients that were treated with additional surgical resection and those that were simply followed up after ESD.
Conclusions: Non-curative resection in SM-GC does not always lead to cancer recurrence. Thus, if additional surgery cannot be performed because of the patient's unsuitable condition or refusal, a close follow-up with endoscopy can be considered as an alternative for carefully selected patients. Moreover, as the ESD technology continues to evolve, it might be possible to expand the criteria for curative ESD in patients with SM-GC.