Extended indication of endoscopic resection for mucosal early gastric cancer: analysis of a single center experience.

Background: Endoscopic resection (ER) has become an important therapeutic option for early gastric cancer (EGC). Some investigators have suggested that this indication should be extended. We aimed to compare the extended indication of ER for intramucosal EGC based on data from a large, single-center study.

Methods: We assessed lymph node metastasis (LNM) status in 1721 intramucosal EGC patients who underwent surgery to evaluate the potential of extension of the ER. We investigated LNM according to Japanese extended criteria; differentiated mucosal cancers irrespective of ulcer less than 30 mm (Criteria I); differentiated mucosal cancers without ulceration irrespective of tumor size (Criteria II), undifferentiated less than 20 mm without ulceration (Criteria III). We also tried to find the groups which have no and minimal risk of lymph node metastasis.

Results: The rate of LNM of mucosal cancer was 2.6% (45/1721). There was minimal lymph nodal metastasis risk for criteria I (0.28%, 2/726, 95% Confidence Interval [CI], 0-0.66%), and criteria II (0.23%, 2/882, 95% CI, 0-0.54%). For criteria III, there was significant lymph node metastasis risk (1.15%, 3/261, 95% CI, 0-2.44%). There was no lymph node metastasis in differentiated mucosal cancer less than 20 mm irrespective of ulcer (0%, 0/501, 95% CI 0-0.73%). The differentiated mucosal cancer group irrespective of ulcer and tumor size have a minimal risk of metastasis (0.43%, 4/941, 95% CI, 0-0.84%)

Conclusion: Our data support extension of the ER indication for the differentiated mucosal EGC. However, undifferentiated lesions without ulceration and smaller than 20 mm were associated with significant metastasis.