Impact of Dose Intensity on Pathologic Complete Response Rate in HER2-Positive Breast Cancer Patients Receiving Neoadjuvant Docetaxel, Carboplatin, Trastuzumab and Pertuzumab (TCHP)

Background Neoadjuvant chemotherapy is the cornerstone treatment for locally advanced breast cancer. Balancing toxicity and efficacy are a common concern of patients treated with chemotherapy. Objective The objective of this study was to determine the impact of dose intensity on pathologic complete response (pCR) at the time of surgery in patients with human epidermal growth factor receptor 2-positive (HER2+) breast cancer. Patients and Methods A retrospective, single-center review was conducted on patients with HER2+ breast cancer who received neoadjuvant docetaxel, carboplatin, trastuzumab and pertuzumab (TCHP) followed by definitive surgery. Results A total of 159 patients were included in the analysis; pCR was obtained in 66 patients (42%). There was no statistically significant difference between the mean dose intensity of each of the individual agents in TCHP and pCR rates. The mean overall dose intensity of docetaxel, carboplatin, trastuzumab and pertuzumab was 90.5%, 90.9%, 97.5%, and 93.9%, respectively. Although higher chemotherapy dose intensity (> 85%) was associated with higher pCR rates, no statistically significant difference was found compared with chemotherapy dose intensity < 85%. The TCHP regimen was difficult to tolerate; 104 patients (65%) required a dose reduction or dose delay during treatment due to toxicity. Conclusion The TCHP regimen, which combines chemotherapy and HER2-directed therapy is effective at obtaining pCR in patients with locally advanced HER2+ breast cancer. These results suggest that the dose intensity of the individual agents did not have a significant impact on pCR rates. Given these findings, providers may be more comfortable allowing dose reductions for greater patient tolerability without sacrificing efficacy.