Important considerations when contemplating endoscopic resection of undifferentiated-type early gastric cancer.

Endoscopic resection (ER) of undifferentiated-type early gastric cancer (UD-EGC) has a lower curative resection (CR) rate than does ER of differentiated-type EGC (D-EGC). However, a low CR rate does not mean that it is unreasonable to schedule ER of UD-EGC. If ER is in fact curative, the long-term outcomes including survival rate are excellent. Quality of life is good because maximal stomach preservation is possible. However, UD-EGC and D-EGC differ histologically. Thus, when ER is contemplated to treat UD-EGC, a careful approach employing strict criteria is essential because the biology of UD-EGC and D-EGC differ.