[en] We studied the relationship between clinicopathologic findings and effect of adjuvant therapy on brain metastasis in breast cancer in order to clarify risk factors for brain metastasis in breast cancer patients. We divided patients into a group treated up until December 1999 (Group 1) and a group treated after January 2000 (Group 2), in whom adjuvant therapy was not generalized. Estrogen receptor-negative patients and cases more advanced than T2 showed a high risk of brain metastasis. The time interval to brain metastasis in Group 1 and 2 were 25 and 49.6 months, respectively, showing a significant difference. Taxan derivatives were used in 1.6% of Group 1 and 76% of Group 2. Estrogen receptor negativity, cancer more advanced than T2, and adjuvant therapy are risk factors for brain metastasis. (author)