Endoscopic submucosal dissection versus surgery for patients with undifferentiated early gastric cancer

Background and aims: endoscopic submucosal dissection (ESD) is the standard treatment for differentiated early gastric cancer (EGC). However, its expanded indication for undifferentiated EGC is controversial. In this study, the ef-ficacy and safety of ESD versus surgery in patients with un-differentiated EGC were compared. Methods: four databases were searched until February 24, 2022, for studies assessing patients with undifferentiated EGC that met an expanded indication for endoscopic re-section and who were treated with ESD or surgery. Prima-ry outcomes were all-cause mortality and any recurrence. Secondary outcomes were complete histological resection, local recurrence, metach ronous recurrence, synchronous recurrence, distant metastasis, overall complication, and bleeding. All meta-analyses were performed using a ran-dom-effects models. Unadjusted (risk ratio [RR]) and ad-justed (aRR and hazard ratio [aHR]) estimates with 95 % confidence interval (CI) were calculated. Results: seven cohort studies were included (n = 2637). The use of ESD was significantly associated with higher all-cause mortality compared to surgery (RR, 2.17; 95 % CI, 1.24-3.81); adjusted all-cause mortality effects were not significant (aRR, 2.28; 95 % CI, 0.95-5.47 and aHR, 1.97; 95 % CI, 0.85-4.53). ESD was associated with a higher risk of any recur rence using unadjusted (RR, 5.24; 95 % CI, 1.49-18.46) and adjusted (aRR, 7.89; 95 % CI, 1.52-40.95 and aHR, 3.73; 95 % CI, 1.17-11.90) estimates. The risk of local recurrence, syn-chronous recurrence and bleeding were significantly higher for ESD versus surgery. No significant differences were found for other secondary outcomes.Conclusions: although ESD is associated with a higher risk of any recurrence, adjusted all-cause mortality is similar during follow-up. Overall complications were similar between ESD and surgery.