[Feasibility and Toxicity of EC-T Dose-Dense Adjuvant Chemotherapy: A Real World Study in Chinese Early-Stage Breast Cancer Patients with High Recurrence Risk].

Objective: We aimed to examine the feasibility and toxicity of EC-T dose-dense regimen and to demonstrate the suitable dose of epirubicin in a Chinese early-stage breast cancer population with high recurrence risk. Methods: 370 patients with early-stage breast cancer at high risk of recurrence were treated with EC-T dose-dense adjuvant chemotherapy and prophylactic administration of recombinant human granulocyte stimulating factor (G-CSF). The incidence of delayed chemotherapy, drug reduction and adverse reactions were retrospectively analyzed. Results: 370 patients completed the planned eight cycles of chemotherapy, 50 patients experienced chemotherapy delay, and 90 had chemotherapy dose reductions. Overall, 61.1% of the patients experienced grade 3 or 4 hematology toxicities, 4.1% of the patients experienced grade 3 gastrointestinal toxicity, 16.3% experienced grade 3 or 4 liver malfunction, and 1.9% experienced grade 3 alopecia. In the multivariate analysis, pretreatment epirubicin levels were associated with comprehensive and hematology toxicity risk (OR=1.268, P=0.046; OR=1.244, P=0.036). With G-CSF support, the probability of grade 3-4 dose limiting toxicity, i. e. neutropenia, abnormal liver function, and gastrointestinal adverse effects did not increase as the epirubicin dose level increased(P>0.05). However, there were no statistically significant associations between epirubicin grade and treatment delay (P=0.814) or dose reduction (P=0.282). Conclusions: EC-T dose-dense chemotherapy shows tolerable toxicity. High dose level is not a limiting factor for this regimen. With G-CSF support, epirubicin 85-90 mg/m(2) is appropriate tolerance dose for Chinese early breast cancer patients with high recurrence risk.