Side Effects of Standard Adjuvant and Neoadjuvant Chemotherapy Regimens According to Age Groups in Primary Breast Cancer

Background: Elderly breast cancer patients are underrepresented in clinical trials and this leads to a lack of knowledge regarding the tolerance and side effects of modern chemotherapy regimens, especially in dose-dense (dd) or dose-intensified combination. Patients and Methods: In this analysis, data from 4 German, randomized (neo-)adjuvant trials, including anthracycline-based chemotherapy, were evaluated for toxicity, compliance and feasibility. Patients were grouped according to age. Results: Of the 4,775 patients, 73.6% were < 60 years, 15.8% were 60-64 years and 10.6% were > 64 years. The patients' compliance decreased with increasing age, the rate of therapy discontinuations was 10.3%; 16.0% were > 64 years old (p < 0.001). The rate of dose reductions also increased with increasing age in the docetaxel/doxorubicin/cyclophosphamide (TAC) (p overall = 0.02) and 5-fluorouracil/epirubicin-cyclophosphamide (FE120C) (p overall < 0.001) treatment groups. Neutropenia grade 3 + 4 in patients of > 64 years was 77% in FE120C- compared to 55% in TAC-treated patients (with primary granulocyte colony-stimulating factors (G-CSFs)). The incidence of febrile neutropenia (FN) was lowest in the regimens without additional taxanes. FN in patients aged > 64 years was lower in the FE120C- than in TAC- and dd-doxorubicin/docetaxel-treated groups. Conclusion: The range and intensity of toxicity increased with age. Neutropenia did not increase significantly in the dd groups; the highest rate was seen in FE120C-treated patients. FE120C without G-CSFs is not an option in patients older than 64 years.