Rationale for the use of gemcitabine in breast cancer (Review)

Many active cytotoxic drugs and several regimens exist for breast cancer therapy. However, these conventional treatments have not changed the outcome of patients with locally advanced and metastatic disease. As a consequence, the dynamic balance between chemotherapy-induced side effects and benefits attributable to relief of cancer-related symptoms must be carefully considered in this setting. Gemcitabine is a pyrimidine nucleoside antimetabolite that has shown activity in a variety of solid tumors, a good toxicity profile, and non-overlapping toxicity with other chemotherapeutic drugs. As a single agent, gemcitabine yields response rates ranging from 14 to 37% as first-line treatment for advanced breast cancer and 12-30% as salvage therapy for patients previously treated with anthracycline and/or taxane treatment. Combined with vinorelbine, platinum, anthracyclines, and taxanes as doublets or triplets, response rates of 50 to 80% have been reported in phase II clinical studies. Gemcitabine in combination with anthracyclines and taxanes has been evaluated in the neoadjuvant setting in patients with early-stage breast cancer with interesting clinical and pathological response rates. Preliminary results of gemcitabine in combination with the biologic agent, trastuzumab, are encouraging. Phase III trials of gemcitabine combinations compared to standard regimens are ongoing with the aim to assess the independent contribution of gemcitabine.