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)

Asian J Endosc Surg. 2015 Nov;8(4):419-23. doi: 10.1111/ases.12204. Epub 2015 Jul 15.


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.

Keywords: Laparoscopic surgery; randomized controlled trial; success rate of informed consent.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Colectomy / methods*
  • Colonic Neoplasms / pathology
  • Colonic Neoplasms / surgery*
  • Female
  • Humans
  • Informed Consent / statistics & numerical data*
  • Japan
  • Laparoscopy*
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Patient Selection*
  • Prospective Studies