Supplementary Material for: Comparison of Safety and Outcomes between Endoscopic and Surgical Resections of Intermediate-risk Primary Gastric Gastrointestinal Stromal Tumors

The objective of this study was to compare the safety and efficacy of endoscopic resection with surgical resection in the treatment of intermediate-risk gastric GISTs, and to further evaluate whether imatinib adjuvant treatment is necessary for resected intermediate-risk gastric GIST by ER. Methods: We retrospectively studied 128 cases for intermediate-risk gastric GISTs that were distributed in endoscopic (n=33) and surgical groups (n=95) at our center between December 2009 to July 2020. We statistically compared the clinical features, pathological reports, perioperative data, and long-term follow-up outcomes. Results: Compared with the surgery group, the endoscopy group was associated with smaller tumor size (2.4±1.0 vs 6.0±1.7cm, P<0.001), shorter operating time (67.3 ±36.5 vs 145.9±74.8min, P<0.001), fewer incidence of short term post-operative complications (3% vs 32.6%, P=0.002). Shorter post-operative hospital days (4.5±1.4 vs 8.5±2.4d, P<0.001), shorter gastric functional recovery time (P<0.001) and a lower overall medical cost of hospitalization (P<0.001) was detected in the endoscopy group. During the median 44.5 months follow-up period , there were no cases of recurrence, metastasis, and death in the endoscopy group. Among 128 patients, 68 accepted adjuvant therapy with imatinib after resection. It was observed that the OS of the adjuvant treatment group with imatinib was lower than that of the group without imatinib (P=0.033). Conclusions: Endoscopic resection for intermediate-risk gastric GIST is a feasible and safe method. And there is no significant benefit for patients with intermediate-risk gastric GIST to accept imatinib adjuvant treatment after ER.

本研究旨在比较内镜切除术（endoscopic resection, ER）与外科切除术治疗中风险胃胃肠道间质瘤（gastrointestinal stromal tumors, GISTs）的安全性与有效性，并进一步评估经内镜切除术切除后的中风险胃GIST患者是否需要接受伊马替尼辅助治疗。方法：本研究回顾性分析了2009年12月至2020年7月期间于本中心收治的128例中风险胃GIST患者，其中内镜组33例、外科组95例。我们对两组患者的临床特征、病理报告、围手术期数据及长期随访结局进行了统计学比较。结果：与外科组相比，内镜组肿瘤体积更小（2.4±1.0 vs 6.0±1.7cm，P<0.001）、手术时长更短（67.3±36.5 vs 145.9±74.8min，P<0.001）、术后短期并发症发生率更低（3% vs 32.6%，P=0.002）；内镜组术后住院时长更短（4.5±1.4 vs 8.5±2.4d，P<0.001）、胃肠功能恢复时间更早（P<0.001），且总体住院医疗成本更低（P<0.001）。在中位随访44.5个月期间，内镜组未出现复发、转移及死亡病例。128例患者中，68例在术后接受了伊马替尼辅助治疗，观察发现伊马替尼辅助治疗组的总生存期（overall survival, OS）低于未接受辅助治疗组（P=0.033）。结论：内镜切除术用于治疗中风险胃GIST是一种可行且安全的术式，对于经内镜切除术切除的中风险胃GIST患者，接受伊马替尼辅助治疗并未带来显著获益。