Selection of candidates for oral etoposide salvage chemotherapy in heavily pretreated breast cancer patients.

Metastatic breast cancer (MBC) is still in most cases an uncurable disease and the main goal of treatment is a good quality of life for these patients. Therefore it is very important to select patients who are appropriate candidates for the particular salvage chemotherapy (CT) schedule. The aim of our study was to assess treatment response to oral etoposide, and to analyze its relationship with patients' and disease characteristics. Seventy-five patients with bidimensionally measurable MBC were included into our study. For most of the patients treatment with etoposide was third-line CT regimen and most of them (90%) had been exposed to previous anthracycline-based CT. Etoposide was administered orally at a dose of 100 mg/day for 10 days every 3 weeks. The overall response rate was 37% (95% CI: 27-50%) with a median time to progression (TTP) and survival of 4.5 and 12 months, respectively. Patients with a long disease-free interval, predominant soft tissue and bone metastases, and less than three metastatic sites responded better to oral etoposide; however, a significantly better response was achieved only in those who had responded to previous CT (46 versus 19%, p=0.04), especially to anthracyclines (50 versus 17%, p=0.016). Response to previous anthracycline-based regimen was the only characteristic that significantly influenced TTP (median TTP: 7 versus 2.5 months, p=0.0066) and survival (median survival: 13.8 versus 5 months, p=0.0072). Toxic side effects were generally mild. Salvage CT with oral etoposide is an appropriate treatment for patients who respond to previous CT, particularly to anthracyclines. It combines a favorable toxicity profile with the major advantage of an oral drug administered at home.