Examination of the response rate of paclitaxel and bevacizumab therapy for metastatic advanced breast cancer according to the lymphopenia grade

Bevacizumab is a well-established anti-VEGF monoclonal antibody that inhibits angiogenesis. Flerein, we examined the response rates according to the grade of lymphopenia in metastatic breast cancer patients treated with bevacizumab+paclitaxel therapy. The objective responses were evaluated according to the Response Evaluation Criteria in Solid Tumors (RECIST) Guideline vii. Toxicity was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) v4.0. Twenty study patients were divided into group A (grade 2-4 lymphopenia) and group B (grade 1 lymphopenia or no decreased lymphocyte count) and compared. The mean progression-free survival (PFS) was 77.7 days in group A (n=7) and 56.8 days in group B (n=13). There was no significant difference between both groups (p"0.67, logrank test). The response rate (RR) was 14.3% (CR=0, PR= 1, SD=3, PD=3) in group A, while in group B, itwas 23.0% (CRO, PR3, SD 6, PD =4). Furthermore, the clinical benefit rate (CBR) was 57.1% in group A and 69.2% in group B.