pT1b esophageal squamous cell carcinoma (ESCC) patients treated by endoscopic resection (ER) required additional treatment with surgical resection (SR) or chemoradiotherapy (CRT) according to 2020 Japan Gastroenterological Endoscopy Society (JGES) guideline. Given the evidences for this recommendation were largely based on small-size studies, our study collected 166 cases of ER-treated pT1b patients in order to investigate the efficacy of additional SR as compared to ER-alone treatment.A multi-institutional retrospective study in China was conducted. The pT1b ESCC treated by ER + SR (n = 42) and ER-alone (n = 124) from 2007 to 2018 were recruited. Meanwhile, patients with positive lymphovascular invasion (LVI(+)) and/or with positive vertical margin (VM(+)) were put into high-risk group, and those with both VM(-) and LVI(-) were selected into low-risk group. The clinicopathological parameters, lymph node metastasis (LNM), and survival between ER + SR and ER-alone groups were analyzed.In high-risk group, concurrent LNM revealed in surgically resected specimens accounted for 52.6% cases in ER + SR group. After surgical removal, the incidence of post-resection LNM dropped down to 5.6%. However, in low-risk group, patients with ER + SR treatment did not exhibit any concurrent LNM in surgically resected specimens, and the incidence of their overall LNM was similar to that in ER-alone group (0% vs. 2.8%, p = 1.000). More importantly, these cases demonstrated significantly shorter overall survival (OS) than that in ER-alone group (81.8% and 100.0%, respectively, at 3 years; log-Rank: P = 0.010).For ER-treated pT1b patients in high-risk group, additional SR is strongly recommended. However, for those in low-risk group, additional SR does not generate much benefit for clearance of LNM, but brings harm to shorten their OS. Therefore, additional SR is not recommended for ER-treated pT1b patient in low-risk group.© 2022. The Author(s).