Endoscopic submucosal dissection for early gastric cancer with undifferentiated-type histology:A meta-analysis

AIM: To evaluate the efficacy and safety of endoscopicsubmucosal dissection(ESD) for early gastric cancer(EGC) with undifferentiated-type histology.METHODS: A systematic literature review was conducted using the core databases. Complete resection,curative resection, en bloc resection, recurrence and adverse event rate were extracted and analyzed. A random effect model was applied. The methodological quality of the enrolled studies was assessed using the Newcastle-Ottawa Scale. Publication bias was evaluated using a funnel plot, the trim and fill method, Egger’s test,and a rank correlation test.RESULTS: Fourteen retrospective studies between2009 and 2014 were identified(972 EGC lesions with undifferentiated-type histology). The total en bloc and complete resection rates were estimated as92.1%(95%CI: 87.4%-95.2%) and 77.5%(95%CI:69.3%-84%), respectively. The total curative resection rate was 61.4%(95%CI: 44.5%-75.9%). The overall recurrence rate was 7.6%(95%CI: 3.4%-16%).Limited to histologically diagnosed expanded-criteria lesions, the en bloc and complete resection rates were91.2% and 85.6%, respectively. The curative resection rate was 79.8%.CONCLUSION: In this analysis, ESD is a technically feasible treatment modality for EGC with undifferentiatedtype histology. Long-term studies are needed to confirm these therapeutic outcomes.