Therapeutic outcomes of endoscopic submucosal dissection of undifferentiated-type intramucosal gastric cancer without ulceration and preoperatively diagnosed as 20 millimetres or less in diameter.

AIM

The aim of the present study was to examine therapeutic outcomes of endoscopic submucosal dissection (ESD) of undifferentiated-type intramucosal gastric cancer and the problems of diagnosis.

METHODS

We reviewed 58 patients with preoperatively diagnosed undifferentiated-type intramucosal early gastric cancer (EGC) without ulceration with a diameter of 20 mm or smaller (expanded-indication lesion) who underwent ESD at the Cancer Institute Hospital between September 2003 and August 2008.

RESULTS

The overall rates of one-piece resection and complete resection were 98% and 90% respectively, and the median operation time was 70 min. Bleeding was seen in 8.6% and perforation in 3.4%. The curative resection rate was low at 79%. Factors responsible for non-curative resection were most commonly submucosal invasions. If limited to pathologically diagnosed expanded-indication lesions, the curative resection rate was 98%. The difference in tumor size between a macroscopic diameter and a histological diameter was within +/-5 mm in 96% of expanded-indication lesions, with none of these cases having a histological diameter that exceeded the macroscopic diameter by more than 5 mm.

CONCLUSION

ESD was technically feasible for expanded-indication lesions of undifferentiated-type EGC. We achieved a high rate of curative resection by the markings at sites 5 mm beyond the preoperatively determined lesion area. Factors responsible for non-curative resection were most commonly submucosal invasions. We should diagnose the depth of such lesions more carefully.