Criteria of tumor response used in clinical trials of chemotherapy.

We have studied 61 published reports of trials of cancer chemotherapy to evaluate the criteria for tumor response that were used and the adequacy of their description in the publication. Our sample comprised recent articles published in three major journals that addressed the influence of chemotherapy on patients with recurrent or metastatic colorectal cancer, non-small cell lung cancer, and head and neck cancer. Incomplete information was sought through a questionnaire mailed to the senior author of each paper, and 48 of them responded. We conclude that: no article contained all of the information required to define precisely criteria for tumor responses; criteria for tumor response are variable; and differences in response criteria contribute to the wide variation in reported rates of tumor response. Meaningful intercomparison of clinical trials will require the establishment of uniform criteria for assessing and reporting the response of tumors to chemotherapy.