A Systematic Review and Pooled Analysis of Studies of Oral Etoposide in Metastatic Breast Cancer.

Objective: Oral etoposide has been used as a later line therapy for metastatic breast cancer for more than twenty years. Its efficacy and clinical usefulness has been suggested in small phase II studies in the metastatic breast cancer population and the drug has also the added advantage of convenient oral administration. Despite these advantages, the place of oral etoposide in treatment of metastatic breast cancer has been challenged in the last decade due to introduction of several other chemotherapeutics, including options available orally, as well as novel targeted therapies. This report pools the data on response rates and survival from all available oral etoposide studies in order to reach a more precise estimate of the clinical benefit of the drug.

Materials and methods: A review of the literature was performed for studies of oral etoposide in metastatic breast cancer. Data were extracted from eligible studies and summary statistics derived. Calculations of pooled response rates and survival estimates were performed according to a random or fixed effect model as appropriate.

Results: The pooled estimate of Response Rate derived from twelve studies found in the English literature was 18.5% (95% CI 11.5-25.5%). The pooled estimate of Clinical Benefit Rate (CBR) was 45.8% (95% CI 38.6-53.0%) and median Overall Survival (OS) approached 1 year. Summarized adverse effects profile data show an overall manageable toxicity.

Conclusion: This pooled analysis provides evidence of a moderate clinical effectiveness of oral etoposide in metastatic breast cancer that could be useful in situations that options are limited but active treatment still appropriate.