[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.