The international conference of adjuvant therapy for primary breast cancer in St. Gallen and the National Institute of Health Consensus Conference for Breast Cancer Treatment have recommended appropriate treatment for individual subgroups by recurrence risk. However, evidence provided by Japanese clinical trials did not contribute to the consensus recommendations. To compare the risk of recurrence in breast cancer patients between Japan and western countries, a database of Japanese breast cancer patients was analyzed. From 1991 to 2001, approximately 12100 articles listed on MEDLINE were reviewed by abstract, and articles were then selected and reviewed by the authors. According to the AHPC (Agency for Health Care Policy and Research), quality assessment and strength for recommendation of the evidence from clinical trials were classified. Even though there are likely some unknown ethnic differences, we should provide Japanese patients with state of the art treatment for breast cancer in accordance with global standard therapies, which have been evaluated by breast cancer specialists in western countries.