Real-world neoadjuvant and adjuvant Trastuzumab-containing regimen patterns and their association with survival among patients with operable HER2-positive breast cancer from 2007 to 2021

Purpose: Chemotherapy in combination with trastuzumab is the standard neoadjuvant and adjuvant therapy for human epidermal growth factor receptor 2 (HER2)-positive breast cancer (BC). Assessing the regimens administered to patients with HER2-positive BC in the real world is lacking. We evaluated neoadjuvant and adjuvant regimen patterns among HER2-positive BC patients (2007 to 2021) identified in a health insurance claims database. Methods: Female BC patients ≥ 18 years who received chemotherapy, surgery, and trastuzumab were chosen from Optum’s de-identified Clinformatics® Data Mart database. Summary statistics, Joinpoint models, Kaplan–Meier survival curves, and Cox regression models were used to analyze the data. Results: We identified 6474 patients (median age 60 years), 71.7% were White, 10.9% were Black, 8.6% were Hispanic, 4.1% were Asian, and 4.7% had unknown race/ethnicity. About 33.8% received neoadjuvant therapy and neoadjuvant therapy use increased with an annual percent change of 10.24% (P <.001). The three most common regimens were adjuvant docetaxel, carboplatin, and trastuzumab (TCH; 29.0%); adjuvant paclitaxel and trastuzumab (17.7%); and neoadjuvant TCH with pertuzumab followed by adjuvant trastuzumab (17.7%). The 5-year overall survival (OS) was 96% (95% CI, 95–96%). Patients had an increased risk of death if they were ≥ 59 years at diagnosis, had a health maintenance organization or other insurance plan, had dual Medicare/Medicaid eligibility, had a mastectomy, did not receive 18 cycles of trastuzumab, or received regimens not recommended by the National Comprehensive Cancer Network. Conclusion: Treatment regimen patterns for HER2-positive BC evolved in correspondence with the U.S. Food and Drug Administration's approval of new drugs for this cancer and National Comprehensive Cancer Network treatment guidelines.