Trastuzumab and chemotherapy after the treatment failure of lapatinib for HER2-positive metastatic breast cancer.

We describe a patient with human epidermal growth factor receptor type 2 (HER2/c-erbB-2)-positive metastatic breast cancer who survived for approximately 6 years after the initiation of combination therapy with trastuzumab and varying types of chemotherapeutic agents. The patient was a 48-year-old postmenopausal female who underwent partial mastectomy with axillary node dissection for cancer of the right breast in March 1994. She developed lung metastases 2 years thereafter, but survived free of relapse for 8 years following chemotherapy and pulmonary lobectomy. The patient failed to respond to lapatinib, a HER1 (EGFR)/HER2 tyrosine kinase inhibitor, received during the course of her treatment but then again responded to subsequently administered trastuzumab. Primary treatment with trastuzumab and paclitaxel was initiated in April 2004 when the patient developed hepatic metastases 8 years after undergoing surgery for lung metastases. Long-term combination therapy with continued trastuzumab and a variety of chemotherapeutic agents was administered for 6 years without any significant adverse events. We discuss the treatment strategies for HER2-positive breast cancer and the role of lapatinib, a recently approved anticancer drug.