Well‐designed and properly conducted surgical clinical trials: Randomized control trials and big database analyses

Watanabe et al revealed safety, efficacy, and operability of an absorbable adhesion barrier in primary rectal cancer surgery with randomized controlled trial (RCT), 1 Ogawa et al reported evaluation of clinical outcomes for colorectal cancer presenting as an oncologic emergency with propensity-score matching (PSM), 2 and Yamamoto et al evaluated the factors on the incidence of adhesive small bowel obstruction with a large-scale study using a national inpatient database. 3 The goal of clinical research is to obtain medically useful evidence through the collection of data on human subjects. Observational studies are conducted by observing medical records of individuals or groups as they are and analyzing the data, without any intended direct intervention, and contain cross-sectional studies in which subjects are observed only once and longitudinal studies in which subjects are observed two or more times. Regarding the usefulness of RCTs versus observational studies using big databases, it has been reported that the results of the latter were comparable to those of RCTs by comparing primary endpoints. 5 Thus, a high level of evidence can be expected by selecting a study design suitable for validating the research hypothesis and determining the number of cases to be analyzed, after incorporating the clinical questions (CQs) into the research questions (RQs).