Is radical surgery necessary in all patients who do not meet the curative criteria for endoscopic submucosal dissection in early gastric cancer? A multi-center retrospective study in Japan.

Background: Although radical surgery is routinely performed for patients who do not meet the curative criteria for endoscopic submucosal dissection (ESD) for early gastric cancer (EGC) due to the risk of lymph node metastasis (LNM), this standard therapeutic option may be excessive given the lower number of patients with LNM. Therefore, we aimed to investigate long-term outcomes and validate risk factors predicting recurrence after ESD.
Methods: Of 15,785 patients who underwent ESD for EGC at 19 institutions between 2000 and 2011, 1969 patients not meeting the curative criteria were included in this multi-center study. Based on the treatment strategy after ESD, patients were divided into radical surgery (n = 1064) and follow-up (no additional treatment, n = 905) groups.
Results: Overall survival (OS) and disease-specific survival (DSS) were significantly higher in the radical surgery group than in the follow-up group (p < 0.001 and p = 0.012, respectively). However, the difference in 3-year DSS between the groups (99.4 vs. 98.7 %) was rather small compared with the difference in 3-year OS (96.7 vs. 84.0 %). LNM was found in 89 patients (8.4 %) in the radical surgery group. Lymphatic invasion was found to be an independent risk factor for recurrence in the follow-up group (hazard ratio 5.23; 95 % confidence interval 2.01-13.6; p = 0.001).
Conclusions: This multi-center study, representing the largest cohort to date, revealed a large discrepancy between OS and DSS in the two groups. Since follow-up with no additional treatment after ESD may be an acceptable option for patients at low risk, further risk stratification is needed for appropriate individualized treatment strategies.