A retrospective evaluation of chemotherapy dose intensity and supportive care for early-stage breast cancer in a curative setting.

Early-stage breast cancer (ESBC) is commonly treated with myelosuppressive chemotherapy, and maintaining full-dose chemotherapy on the planned schedule is associated with improved patient outcome. Retrospective analysis of patients with ESBC treated from 1997 to 2000 showed that 56 % of patients received a relative dose intensity (RDI) <85 % (Lyman et al., J Clin Oncol 21(24):4524-4531, 2003). To determine current practice, we evaluated treatment patterns at 24 US community- and hospital-based oncology practices, 79 % of which participated in the previous study. Data were abstracted from medical records of 532 patients with surgically resected ESBC (stage I-IIIa) treated from 2007 to 2009, who were ≥18 years old and had completed ≥1 cycle of one of the following regimens: docetaxel + cyclophosphamide (TC); doxorubicin + cyclophosphamide (AC); AC followed by paclitaxel (AC-T); docetaxel + carboplatin + trastuzumab (TCH); or docetaxel + doxorubicin + cyclophosphamide (TAC). Endpoints included RDI, dose delays, dose reductions, grade 3/4 neutropenia, febrile neutropenia (FN), FN-related hospitalization, granulocyte colony-stimulating factor (G-CSF) use, and antimicrobial use. In this study, TC was the most common chemotherapy regimen (42 %), and taxane-based chemotherapy regimens were more common relative to the previously published results (89 vs <4 %). Overall, 83.8 % of patients received an RDI ≥85 %, an improvement over the previous study where 44.5 % received an RDI ≥85 %. Other changes seen between this and the previous study included a lower incidence of dose delays (16 vs 25 %) and dose reductions (21 vs 37 %) and increased use of primary prophylactic G-CSF (76 vs ~3 %). Here, 40 % of patients had grade 3/4 neutropenia, 3 % had FN, 2 % had an FN-related hospitalization, and 30 % received antimicrobial therapy; these measures were not available in the previously published results. Though RDI was higher here than in the previous study, 16.2 % of patients still received an RDI <85 %. Understanding factors that contribute to reduced RDI may further improve chemotherapy delivery, and ultimately, patient outcomes.