Success Rate Of Informed Consent Acquisition And Factors Influencing Participation In A Multicenter Randomized Controlled Trial Of Laparoscopic Versus Open Surgery For Stage Ii/Iii Colon Cancer In Japan (Jcog0404)

Introduction: Successful completion of randomized controlled trials (RCT) is dependent on informed consent (IC) acquisition from patients. The aim of this study was to prospectively calculate the proportion of participation in a surgical RCT and to identify the reasons for failed IC acquisition.Methods: A 30-institute RCT was conducted to evaluate oncological outcomes of open and laparoscopic surgery for stage II/III colon cancer (JCOG0404: UMIN-CTR C000000105). The success rate of obtaining IC, which was supported by a DVD that helped patients understand this trial, was evaluated in eight periods between October 2004 and March 2009. In addition, reasons for failed IC acquisition were identified from questionnaires.Results: A total of 1767 patients were informed of their eligibility for the trial, and 1057 (60%) were randomly assigned to either the laparoscopic surgery (n = 529) or open surgery (n = 528) group. The success rate of IC acquisition ranged from 50% to 62% in eight periods. The most common reasons for failed IC acquisition were anxiety/unhappiness about the randomization, patients' preference for one form of surgery, and strong recommendations from referring doctors or relatives.Conclusions: With the assistance of a DVD, high success rates of IC acquisition were obtained for an RCT of laparoscopic versus open surgery for stage II/III colon cancers. To obtain such a rate, investigators should make efforts to inform patients, their relatives, and referring doctors about the medical contributions a surgical RCT can make.