Retrospective analysis of the use of G-CSF and its impact on dose response for anthracycline plus taxane-based schedules in early breast cancer

PURPOSE: To evaluate the impact on survival of the relative dose intensity (RDI) achieved in patients with early breast cancer receiving anthracycline plus taxane-based chemotherapy in the adjuvant setting. PATIENTS AND METHODS: Patients with early breast cancer diagnosed from January 1999 through December 2006 were included. Dose intensity was evaluated according to the number of delayed cycles and days and the percentage of RDI. RESULTS: A total of 231 breast cancer patients were included. Granulocyte colony-stimulating factor (G-CSF) was given to 39 % of patients. Few patients delayed chemotherapy administration ≥2 cycles (6 %) and ≥15 days (2 %), and the majority of them received ≥85 % of the RDI (98 %). Overall survival was statistically lower at 5 years in patients who received <85 % of RDI in comparison with those who received ≥85 % of RDI (80 vs. 97 %; p = 0.026). CONCLUSIONS: With a wide use of G-CSF in patients treated with adjuvant anthracyclines plus taxane-based schedules, 98 % of patients received a RDI ≥85 %. A significant although inconsistent impairment of survival was found in those patients with lower RDI.