Chemoendocrine Metronomic Therapy of Estrogen Receptor-Positive Breast Cancer by Taxanes or Capecitabine in Combination with Aromatase Inhibitors

The intense anticancer therapy using conventional cytostatic drugs is accompanied by serious side effects that restrict the application of the cytostatic drugs. Metronomic therapy as a modern method for administration of low doses of cytostatic agents that in combination with other anticancer drugs induce long lasting tumor dormancy with minimal side effects. Aim: We aimed our study at investigation of the efficacy of a contemporary chemoendocrine metronomic therapy, including cytostatic drugs, such as paclitaxel or capecitabine, in combination with aromatase inhibitors (AI, anastrozole, letrozole), in the treatment of estrogen recepor-positive breast cancer. Presentation of Case: The patient (74 years old) was initially diagnosed with advanced stage pT4bpN2Mx of infiltrative ductal breast carcinoma with lymph, lung and bone metastases. Discussion: Based on high estrogen receptor sensitivity in 67-100% of the analysed tumor cells, endocrine therapy was applied after mastectomy. However, progression of the disease required involvement of systemic cytostatic agents in the therapy. Following the achievements of the contemporary medicine, chemoendocrine metronomic therapeutical protocols, including combination of anastrozole with taxane or capecitabine, were found to induce rapid and continuous disease remission. Conclusion: This case report demonstrated rapid achievement of continuous remission by a contemporary chemoendocrine metronomic treatment of metastatic ER-positive breast cancer in all stages of the therapy: systemic anticancer treatment with weekly paclitaxel plus anastrozole, followed by anastrozole plus low doses of capecitabine and analogous maintenance therapy. The results can be explored in future clinical trials about synergy between hormone inhibitors and cytostatic agents in combination anticancer therapies.