Endoscopic resection for undifferentiated early gastric cancer

Background and Objective: Endoscopic resection (ER) has become an important curative option for early gastric cancer (EGC). However, the application of ER for undifferentiated EGC remains controversial. The aim of this study was to evaluate the clinicopathologic outcomes of ER performed in undifferentiated EGC with special reference to histopathologic subtypes to examine the feasibility of ER in undifferentiated EGC. Design and Setting: Retrospective, single-center study. Patients: From January 2001 to April 2007, 58 lesions in 58 patients with undifferentiated EGC (17 poorly differentiated adenocarcinoma; 41 signet-ring cell carcinoma) were treated by ER at Severance Hospital, Seoul, Korea. Main Outcome Measurements: The therapeutic efficacy of ER was assessed according to en bloc resection, histologic complete resection (CR), lateral or vertical cut end-positive (including submucosal invasion), and recurrence rates in 3- to 65-month follow-up periods. Results: The en bloc resection and CR rates were 84.5% and 67.2%, respectively. The en bloc and CR rates in poorly differentiated were 82.4% and 58.8%, whereas those in signet-ring cell were 85.4% and 70.7%, respectively. There were no significant differences between poorly differentiated and signet-ring cell. However, all (100%) of the histologic incomplete resections in poorly differentiated were vertical cut end-positive, whereas 83.3% of these resections in signet-ring cell were lateral cut end-positive. The recurrence rate was 5.1% in CR during the follow-up period. Limitations: Retrospective, short-term follow-up period. Conclusions: ER may be a feasible local treatment for undifferentiated EGC if CR can be achieved. However, a different approach is necessary between poorly differentiated and signet-ring cell before ER to prevent incomplete resection.