Prognostic Factors Influencing Progression-Free Survival in HER2-Positive Metastatic Breast Cancer Patients Who Were Treated With A Combination of Lapatinib and Capecitabine.

Objective: The aim was to assess the prognostic variables in human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer patients receiving lapatinib plus capecitabine. Materials and Methods: Retrospective data on HER2-positive metastatic breast cancer patients who received lapatinib and capecitabine were analyzed. Survival outcome was obtained with Cox regression analysis and the Kaplan-Meier method. Results: The study included 102 patients. Forty-four (43.1%) patients had de novo metastatic disease. The most frequent metastatic sites were, in order, bone (61.8%), brain (57.8%), liver (35.3%), and lung (34.3%). All of the patients had previously received chemotherapy based on trastuzumab. With combined lapatinib and capecitabine, complete response was observed in 7.8%, partial response in 30.4%, and stable disease in 24.5%. Progression-free survival was 8 (95% confidence interval, 5.1-10.8) months. In multivariable analysis, endocrine therapy (p = 0.02), de novo metastatic disease (p = 0.02), and age (p = 0.02) were prognostic factors for progression-free survival. However, the number of chemotherapy cycles with trastuzumab, palliative radiotherapy, history of breast surgery, and the number of metastatic sites were not significant in this respect. Conclusion: These results have demonstrated the effectiveness of lapatinib plus capecitabine in metastatic HER2-positive breast cancer patients. Furthermore, unfavorable prognostic factors for progression-free survival were shown to be hormone-negative tumor, de novo metastatic disease, and young age.