Efficacy and Safety of Low-Dose Oral Etoposide Combined With Capecitabine for Patients With Postoperative Metastatic Breast Cancer Resistant to Anthracycline/Taxanes.

Introduction: The purpose of this study is to determine the efficacy and safety of metronomic chemotherapy with all-oral combination of low-dose etoposide/capecitabine in patients with metastatic breast cancer (MBC) previously treated with anthracyclines and/or taxanes.

Methods: Metronomic chemotherapy, giving lower, more frequent doses of chemotherapy drugs over an extended period, often without long breaks between cycles. With oral low-dose etoposide + capecitabine was administered to patients who had postoperative MBC resistant to anthracycline/taxanes: etoposide 30 mg/m/day, qd for 7 days + capecitabine 1400 mg/m/day, administered in two equal dose for 14 days, with 21 days as a cycle. Patients received treatments if complete response, partial response, or stable disease was obtained until disease progressed or became intolerable. RECIST criteria were used for standard efficacy evaluation and NCI-CTC version 3.0 was used for evaluation of side effects.

Results: From June 2008 to May 2020, 85 patients received the aforesaid treatment; 67 of these patients were eligible for efficacy and side effects evaluation. After treatment, 6 (8.96%) patients obtained partial response, 41 (61.19%) patients had stable disease, and 20 (29.85%) patients had disease progression. The overall response rate (complete response + partial response) was 8.96%, and disease control rate (complete response + partial response + stable of disease) was 70.15%. Clinical benefits (complete response + partial response + stable of disease ≥ 24 weeks) were obtained for 50% of the patients. The median and mean treatment to progression time was 5 months and 6.06 months (95% CI: 3.43~8.70), respectively. The most common grade I/II side effects were leukopenia and fatigue (15.8%).

Conclusions: For patients with postoperative MBC resistant to anthracycline/taxanes, oral low-dose etoposide + capecitabine was effective with tolerable safety. The patients did not need antiemetics or leukocytic drugs, and the treatment was cost-effective because the patients did not need to be hospitalized for intravenous infusion.