[Lapatinib is useful for metastatic breast cancer patients who cannot be treated with trastuzumab-report of a case].

The patient was a 71-year-old woman. Mammography revealed an irregularly shaped mass in the U area of her left breast. Ultrasonography revealed an irregularly shaped mass in the C area of her breast. The mass was 22 mm in diameter. Core-needle biopsy of the area led to a diagnosis of invasive ductal carcinoma. The lesion was negative for estrogen receptor and progesterone receptor expression and positive for human epidermal growth factor receptor 2 protein expression. Distant metastasis was not detected. Muscle-preserving mastectomy and lymph node dissection were performed. Eight months after the operation, multiple liver metastases were found. We attempted to treat these metastases with trastuzumab. However, an infusion reaction was recognized. Therefore, we attempted treatment with lapatinib and capecitabine. This treatment was administered for 2 months without incident. After 2 months, hand-foot syndrome was recognized. Then, we attempted treatment with lapatinib alone. Lapatinib alone was effective against the multiple liver metastases. The patient's condition has remained stable for 1 year after treatment.