Breast Cancer Res Treat

PurposeTo investigate the impact of chemotherapy relative dose intensity (RDI) on cause-specific and overall survival for stage I\u2013III breast cancer: estrogen receptor or progesterone receptor positive, human epidermal-growth factor receptor negative (ER+/PR+ and HER2 12) vs. triple-negative (TNBC) and to identify the optimal RDI cut-off points in these two patient populations.MethodsData were collected by the Louisiana Tumor Registry for two CDC-funded projects. Women diagnosed with stage I\u2013III ER+/PR+, HER2 12 breast cancer, or TNBC in 2011 with complete information on RDI were included. Five RDI cut-off points (95, 90, 85, 80, and 75%) were evaluated on cause-specific and overall survival, adjusting for multiple demographic variables, tumor characteristics, comorbidity, use of granulocyte-growth factor/cytokines, chemotherapy delay, chemotherapy regimens, and use of hormone therapy. Cox proportional hazards models and Kaplan\u2013Meier survival curves were estimated and adjusted by stabilized inverse probability treatment weighting (IPTW) of propensity score.ResultsOf 494 ER+/PR+, HER2 12 patients and 180 TNBC patients, RDI < 85% accounted for 30.4 and 27.8%, respectively. Among ER+/PR+, HER2 12 patients, 85% was the only cut-off point at which the low RDI was significantly associated with worse overall survival (HR = 1.93; 95% CI 1.09\u20133.40). Among TNBC patients, 75% was the cut-off point at which the high RDI was associated with better cause-specific (HR = 2.64; 95% CI 1.09, 6.38) and overall survival (HR = 2.39; 95% CI 1.04\u20135.51).ConclusionsHigher RDI of chemotherapy is associated with better survival for ER+/PR+, HER2 12 patients and TNBC patients. To optimize survival benefits, RDI should be maintained 65 85% in ER+/PR+, HER2 12 patients, and 65 75% in TNBC patients.R15 MD012387/MD/NIMHD NIH HHS/United StatesU58 DP003915/DP/NCCDPHP CDC HHS/United States1eEDSK0106/Centers for Disease Control and Prevention/5NU58DP003915/Centers for Disease Control and Prevention/2019-05-01T00:00:00Z29368311PMC61907076242vault:3099