[A case of liver metastasis of breast cancer responding to letrozole].

The patient was a 68-year-old woman who had a right mastectomy performed in another hospital in 1987. Her right breast tumor was histologically diagnosed IDC and ER(-), with an uncertain PgR and HER2. Tamoxifen was administered as adjuvant therapy for five years after surgery. Because she had abdominal pain in January, 2007, she consulted her family doctor. At that doctor's hospital, metastatic tumors of the liver were found, and she was therefore referred to our hospital. A liver biopsy of the tumor was conducted in our hospital, and hormone therapy was also conducted because her cancer status was ER(+), PgR(+), HER2(0), and was not life-threatening. Hormone therapy had a good effect on the tumor. ER, PgR and HER2 expression might make the difference between a primary tumor and a metastatic one, as in this case. Therefore, we should perform biopsies on metastatic tumors to determine the best treatment method. There is a possibility that hormone therapy will become an effective therapeutic procedure for breast cancer patients who are hormone receptor positive, are not in a life threatening situation, and have had a long, disease-free survival. We reported one case in which the aromatase third generation inhibitor letrozole was effective for treating liver metastases of breast cancer.