Is Endoscopic Resection an Acceptable Treatment for Undifferentiated EGC?

Background/Aims: Endoscopic resection (ER) is an effective treatment in selected patients with early gastric cancer (EGC). We have evaluated the clinical outcomes of ER in patients with undifferentiated EGCs, including poorly differentiated adenocarcinoma or signet ring cell carcinoma. Methodology: We retrospectively examined the medical records of 77 patients diagnosed with undifferentiated EGC after ER (EMR for 22 patients and ESD for 56 patients) at a single center. Results: The mean +/- SD lesion size was 23.2 +/- 14.1mm. The 77 lesions included 65 (84.4%) intramucosal cancers and 12 (15.6%) involving the submucosal layer. Of these 77 patients, 35 underwent curative resection and 42 did not. After a mean follow-up period of 41 months (range, 9-152), local recurrences were observed in four patients (5.2%), all of whom had not undergone curative resection. No patient died of EGC. Univariate analysis showed that tumor involvement of the resection margins (p<0.001) and lymphatic invasion (p=0.003) were significant risk factors for recurrence after ER in undifferentiated EGCs. However, multivariate analysis did not show any significant risk factors. Conclusions: ER may be an alternative treatment modality for selected patients with undifferentiated EGCs.