Outstanding problems with response evaluation criteria in solid tumors (RECIST) in breast cancer

In 1999 European Organization for Research and Treatment of Cancer, National Cancer Institute of the United States and National Cancer Institute of Canada published Response Evaluation Criteria in Solid Tumors (RECIST) as a revision of the WHO criteria to achieve a unified, objective set of criteria for assessing antitumor activity. The present paper discusses breast cancer assessment using RECIST and discusses various outstanding problems in breast cancer therapy.

The subjects were 50 advanced/recurrent breast cancer patients who were eligible/completed cases and were registered in various clinical trials at Gunma Cancer Center from 1995-2000. The subjects were investigated with regard to the application of RECIST to evaluate the appropriateness and efficacy of the criteria for these patients, in comparison with General Rules for Clinical and Pathological Recording of Breast Cancer formulated by the Japanese Breast Cancer Society (JBCS). In addition, a study was conducted of the survival rate as a function of the initial site of metastasis in 258 recurrent cases.

Of the 50 cases judged to be eligible by the JBCS General Rules, 16 cases (32%) were judged to be ineligible by RECIST. The results using the two sets of criteria were the same for CR and PD, while there were some differences in PR and SD/NC.

To fully adopt RECIST for breast cancer, the following should be discussed further: (1) the exclusion of bone lesions (2) assessment of long NC (3) difference in survival by metastatic lesion site (4) eligible cases are reduced due to the exclusion of target lesions having a diameter of less than 2.0 cm.