Efficacy and Safety of Weekly Paclitaxel in Breast Cancer With Symptomatic Bone Marrow Infiltration.

Background/Aim: Currently, there is no recommendation for the treatment of breast cancer (BC) with bone-marrow cell infiltration (BMI). We evaluated the efficacy and safety of weekly-paclitaxel in this population. Patients and Methods: This retrospective study included all BC patients with BMI receiving weeklypaclitaxel between January 2014 and May 2018. Overallsurvival (OS) was the primary endpoint. Secondary endpoints were progression-free-survival (PFS) and safety. Results: BMI was diagnosed in 26 patients. This infiltration was suggested by peripheral blood smear in 73% of cases. All patients had anemia, and 77% had thrombocytopenia. OS and PFS were 7.2 months [95% confidence interval (CI)=2.6-20.7] and 3.3 months (95%CI=1.6-7.2), respectively. Good performance-status, absence of thrombocytopenia and presence of less than 5% of circulating erythroblasts at BMI diagnosis, were associated with better survival. One patient presented grade 5 febrile neutropenia but no episodes of bleeding were reported. Conclusion: Weekly-paclitaxel is an effective therapeutic option with limited toxicity for BC with BMI.