Long-term outcomes of endoscopic submucosal dissection versus surgery in early gastric cancer meeting expanded indication including undifferentiated-type tumors: a criteria-based analysis.

ABSTRACT

BACKGROUND: Endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) meeting the expanded indication is considered investigational. We aimed to compare long-term outcomes of ESD and surgery for EGC in the expanded indication based on each criterion. METHODS: This study included 1823 consecutive EGC patients meeting expanded indication conditions and treated at a tertiary referral center 916 and 907 patients underwent surgery or ESD, respectively. The expanded indication included four discrete criteria (I) intramucosal differentiated tumor, without ulcers, size >2 cm; (II) intramucosal differentiated tumor, with ulcers, size ≤3 cm; (III) intramucosal undifferentiated tumor, without ulcers, size ≤2 cm; and (IV) submucosal invasion <500 µm (sm1), differentiated tumor, size ≤3 cm. We selected 522 patients in each group by propensity score matching and retrospectively evaluated each group. The primary outcome was overall survival (OS); the secondary outcomes were disease-specific survival (DSS), recurrence-free survival (RFS), and treatment-related complications. RESULTS: In all patients and subgroups meeting each criterion, OS and DSS were not significantly different between groups (OS and DSS, all patients p = 0.354 and p = 0.930; criteria I p = 0.558 and p = 0.688; criterion II p = 1.000 and p = 1.000; criterion III p = 0.750 and p = 0.799; and criterion IV p = 0.599 and p = 0.871). RFS, in all patients and criterion I, was significantly shorter in the ESD group than in the surgery group (p < 0.001 and p < 0.003, respectively). The surgery group showed higher rates of late and severe treatment-related complications than the ESD group. CONCLUSIONS: ESD may be an alternative treatment option to surgery for EGCs meeting expanded indications, including undifferentiated-type tumors.