The effect of reduced RDI of chemotherapy on the outcome of breast cancer patients

The aims of this study were to investigate the impact of the relative dose intensity (RDI) of chemotherapy on disease-free survival (DFS) and overall survival (OS), to identify the optimal RDI cut-off points with the docetaxel, epirubicin and cyclophosphamide (TEC) regimen for stage I–III breast cancer patients and to explore the adverse events in these patients. To achieve this, we performed a retrospective analysis of breast cancer patients treated at the First Affiliated Hospital of Chongqing Medical University in 2011. The results showed that among 293 patients with the TEC regimen, 85% and 80% were the cut-off points at which a high RDI was associated with better overall survival (HR = 2.04; 95% CI 1.13, 3.70; p = 0.02) and disease-free survival (HR = 1.97; 95% CI 1.14–3.42; p = 0.02), respectively. Among 169 HR(+) patients, 80% was the cut-off point for DFS (HR = 2.33; 95% CI 1.07–5.08; p = 0.03), and 85% was the cut-off point for OS (HR = 3.00; 95% CI 1.24–7.26; p = 0.02). Among 105 HR(−) patients, 80% was the cut-off point for OS (HR = 2.86; 95% CI 1.05–7.80; p = 0.04). Of 293 patients, neutropenia, nausea, and vomiting were found to be correlated with the level of RDI. In conclusion, a higher RDI of chemotherapy is associated with better survival but with a higher probability of causing adverse events. To optimize survival benefits, the RDI should be maintained ≥ 85% for HR(+) patients and ≥ 80% for HR(−) patients.