Relative dose intensity delivered to patients with early breast cancer: Canadian experience

Adjuvant chemotherapy for early breast cancer improves disease-free and overall survival in pre- and postmenopausal women. The importance of maintaining relative dose intensity (RDI) is well-known; however, little information is available from routine clinical practice regarding how well dose intensity is maintained with modern chemotherapy regimens. In a retrospective review of patients undergoing chemotherapy for early breast cancer at a single institution in Canada from January 2006 to November 2007, a total of 263 patients received one of the following regimens: AC-T [doxorubicin (Adriamycin: Pharmacia, Kalamazoo, MI, U.S.A.)-cyclophosphamide, paclitaxel (Taxol: Bristol-Myers Squibb, Princeton, NJ, U.S.A.)] FEC-100 (5-fluorouracil-epirubicin-cyclophosphamide) FFC-D (5-fluorouracil-epirubicin-cyclophosphamide, docetaxel) Overall, only 14.4% of patients had a RDI less than 85%. Dose delay or reduction (or both) occurred in 46%, 37%, and 20% of patients receiving FEC-100, AC-T, and FEC-D respectively. Optimal RDI was delivered to 96%, 95%, and 70.7% of patients for AC-T, FEC-D and FEC-100 regimens respectively. Patients over 65 years of age accounted for 14% of the total cohort and were more likely to receive a suboptimal RDI than were patients younger than 65 years of age (35% vs. 6.6%). Optimal chemotherapy RDI (>85%) for early breast cancer can be achieved at an academic cancer centre. This goal is less often accomplished in elderly patients, and thus a proactive approach is required for managing toxicity in that Population.