Use of CA-125 to assess response to new agents in ovarian cancer trials

J Clin Oncol. 2003 May 15;21(10 Suppl):187s-193s. doi: 10.1200/JCO.2003.01.223.


The purpose of this article is to demonstrate how CA-125 could be used in clinical trials to ascertain the efficacy of new drugs for ovarian cancer. Studies that have investigated the use of CA-125 in assessing response and progression of ovarian cancer are reviewed. A precise CA-125 response definition that requires either a 50% or 75% decrease in CA-125 levels has been shown in trials of both initial chemotherapy and in phase II trials to predict accurately the response in comparison with standard response criteria. A simpler response definition that is based on just a 50% decrease in CA-125 levels has been proposed by the Gynaecological Cancer Intergroup (GCIG) but requires further validation. Definitions for progression have also been proposed by the GCIG on the basis of a confirmed doubling of CA-125 levels from either the upper limit of normal or the nadir CA-125 level. These CA-125 definitions for progression falsely predict progression in fewer than 2% of patients and can be used to define the date of progression. Precise definitions for response and progression according to CA-125 should be incorporated into ovarian cancer clinical trial protocols. These definitions already have been shown to be valuable in assessing efficacy of new agents but require further prospective evaluation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Antineoplastic Agents / therapeutic use*
  • CA-125 Antigen / blood*
  • Clinical Trials as Topic / methods
  • Disease Progression
  • Drugs, Investigational / therapeutic use*
  • Female
  • Humans
  • Ovarian Neoplasms / drug therapy*
  • Ovarian Neoplasms / immunology
  • Patient Selection
  • Recurrence
  • Research Design
  • Treatment Outcome


  • Antineoplastic Agents
  • CA-125 Antigen
  • Drugs, Investigational