Abstract: Diagnosis and treatment of primary rectal gastrointestinal stromal tumors         ZHANG Peng*, WANG Ming, LIN Guo-le, et al. *Department of Gastrointestinal Surgery, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
Corresponding authors：TAO Kai-xiong, E-mail: kaixiongtao@hust.edu.cn; CAO Hui，E-mail: caohuishcn@hotmail.com; ZHANG Bo, E-mail: Zhangbo7310@126.com
ZHANG Peng, WANG Ming, LIN Guo-le, FENG Fan are the first authors who contributed equally to the article.
Abstract    Objective    To analyze the clinical and pathological features of rectal gastrointestinal stromal tumors (GIST) and the strategies of surgical treatment. Methods    The clinicopathological and follow-up data of patients with rectal GIST who underwent surgical treatment in 11 medical centers in China from January 2000 to December 2019 were analyzed retrospectively. Basic information, laboratory examinations, imaging examinations, preoperative therapy, surgery, postoperative conditions, postoperative pathology and follow-up were included. The nearest neighbor matching of propensity score matching method (PSM) was conducted to reduce differences in baseline levels between groups. The Kaplan-Meier method was used to calculate the survival rate. Results    A total of 340 patients with rectal GIST were enrolled, including 211 males (62.1%) and 129 females (37.9%), with a median age of 54 years; the median diameter of the tumor at the first diagnosis was 5.1 cm, and the median distance from inferior margin of the tumor to anal verge was 5.0 cm. During 2000 to 2010, 2011 to 2013, 2014 to 2016 and 2017 to 2019, the proportions of local excision were 31.3%, 34.3%, 42.6%, and 38.2%, respectively; the proportions of preoperative therapy were 6.0%, 7.5%, 33.7%, and 47.2%, respectively; the proportions of genetic testing were 7.2%, 9.0%, 30.7%, and 32.6%, respectively; the proportions of adjuvant treatment for patients with intermediate- and high-risk were 21.1%, 24.2%, 45.9%, and 47.1%, respectively. One hundred and twenty-six cases (37.1%) underwent local excision and 214 cases (62.9%) underwent radical resection. Before PSM, patients underwent local excision had smaller tumor size (P<0.001), fewer mitotic count (P<0.001), closer distance to anal verge (P<0.001), and higher rate of preoperative therapy (P=0.036); the operation time, anus preservation rate, postoperative complications and postoperative hospital stay of local excision group were better than those of radical resection group. After PSM, 148 patients were included. The gender, age, distance from the tumor to the anal verge, tumor size,  mitotic count and postoperative complications were not significantly different between the two groups (all P>0.05). The operation time, anus preservation rate, and postoperative hospital stay of local excision group were better than radical resection group. The median follow-up time was 52 (1 to 215) months with the following rate of 89.4%. Among 340 cases, 59 cases (17.4%) relapsed, and the 3-year and 5-year recurrence-free survival rates were 88.4% and 81.6%, respectively. There was no significant difference in the prognosis of local excision and radical resection groups before(P=0.856) and after PSM (P=0.065). Conclusion    Rectal GIST mainly locates in the lower rectum, mostly occurs in aging men. Under the premise of complete resection, local excision has better short-term outcomes than radical resection, and the long-term outcomes of the two groups are comparable.

Key words: gastrointestinal stromal tumor, rectum, surgery, targeted therapy, prognosis

摘要： 目的    分析原发直肠胃肠间质瘤（GIST）临床病理特征，探讨其外科诊治策略。方法    回顾分析2000年1月至2019年12月国内11家医疗中心行手术治疗的340例原发直肠GIST病人临床病理及随访资料。统计资料包括病人基本信息、实验室检查、影像学检查、术前治疗、手术及术后情况、术后病理学检查结果及随访数据。应用倾向性评分匹配的最近邻匹配法减少组间基线水平差异；采用Kaplan-Meier法（Log-rank检验）计算生存率。结果    340例病人中，男性211例（62.1%），女性129例（37.9%），中位确诊年龄54（16～84）岁；初诊时肿瘤中位直径为5.1 cm，肿瘤下缘距肛缘中位距离为5.0 cm。2000—2010年、2011—2013年、2014—2016年及2017—2019年期间局部切除术比例分别为31.3%、34.3%、42.6%、38.2%；术前治疗比例为6.0%、7.5%、33.7%、47.2%；基因检测比例为7.2%、9.0%、30.7%、32.6%；中高危病人辅助治疗比例为21.1%、24.2%、45.9%、47.1%。340例病人中126例（37.1%）行局部切除术，214例（62.9%）行根治性切除术；倾向评分匹配前，局部切除组病人肿瘤直径小（P<0.001），核分裂象少（P<0.001），肿瘤距肛缘距离近（P<0.001），术前治疗比例高（P=0.036）；在手术时间、肛门保留率、术后并发症及术后住院时间方面优于行根治性切除术病人。倾向评分匹配后，两组分别纳入74例病人，两组病人性别、年龄、肿瘤距肛缘距离、肿瘤直径差、核分裂象及术后并发症差异无统计学意义（均P>0.05），局部切除组在手术时间、肛门保留率及术后住院时间方面优于行根治性切除病人。340例病人中位随访时间为52（1～215）个月，随访率（89.4%）。其中59例（17.4%）复发，3年、5年无复发生存率为88.4%、81.6%。倾向评分匹配前后局部切除组与根治性切除组病人预后差异均无统计学意义（P=0.856，P=0.065）。结论    直肠GIST主要位于下段直肠，多发生于中老年男性；在保证完整切除前提下，局部切除术短期疗效优于根治性切除术，长期疗效两者相当。

关键词: 胃肠间质瘤, 直肠, 手术, 靶向治疗, 预后