[Difficulties and countermeasures of surgical clinical research according to CLASS experience].

Clinical research is a form of scientific study, whose subjects focus on patients. Its main contents include the etiology, diagnosis, treatment and prognosis related to their disease. Its working place is mainly in medical service and institutes. It is organized and conducted jointly by clinical doctors, epidemiologists, statisticians and multidisciplinary experts. Surgical clinical research, different from studies on pharmaceuticals, has inherent limitations, such as difficulties in establishing standardized intervention, designing rigorous control group, achieving real blinded randomization, or setting unified standards for multicenter practice. To overcome these obstacles, the following points should be considered before initiating: (1) clinical problems based on scientific rationale and the principle of "population-intervention-comparison-outcome" (PICO) should be raised. (2) research methods are applied normatively, and "idea, development, exploration, assessment, long-term follow up" (IDEAL) methodology published in Lancet 2009 is recommended for assessment of new surgical techniques. (3) professional research team is built up to accomplish protocol design, study execution, and efficient follow-up collaboratively and successfully. (4) authenticity of clinical data is ensured, and acquisition and verification of data are standardized. Aiming at clinical problems of laparoscopic gastric cancer, Chinese Laparoscopic Gastrointestinal Surgery Study Group (CLASS) established in 2009 has initiated a series of CLASS studies and has led to the rapid development of domestic surgical clinical researches on laparoscopic surgery of gastric cancer like a great fire initiated by spark kindles. Herein, based on the experience of CLASS studies, this review summarizes the difficulties and countermeasures of surgical clinical research, so as to humbly share some experience of our team with fellows and colleagues.临床研究是以患者为主要研究对象，以疾病的病因、诊断、治疗和预后为主要研究内容，以医疗服务机构为主要研究场所，由临床医生、临床流行病学专家、统计专家等多学科人员共同参与组织实施的研究工作。与药物临床研究不同，外科临床研究的开展中，存在干预措施难以标准化、难以建立严格的对照组、难以做到真正的盲法随机以及多中心难以统一准则等难点。为应对这些难点，开展临床研究之前需注意以下几点。（1）科学提出临床问题，需遵循PICO原则，即患病人群（P），暴露或干预因素（I），对照（C）和结局或观察指标（O）。（2）规范应用研究方法，外科新技术的评价可考虑采用2009年发表在Lancet上的IDEAL框架思路。（3）依靠专业的研究团队，包括方案设计、研究执行和专业随访。（4）确保严谨的临床数据，规范数据的采集与核查。针对我国腹腔镜胃癌开展的临床问题，2009年成立的中国腹腔镜胃肠外科研究组（CLASS），开展了CLASS系列研究，并带动了国内腹腔镜胃癌外科临床研究如燎原之势迅速发展起来。本文从CLASS研究开展的经验出发，总结外科临床研究开展的难点与对策，谨与同道分享本团队的一些体会。.