Evolution of neoadjuvant therapy for breast cancer regimens over 12 years and pathologic response rates according to tumor subtypes and clinical stage: A single-center retrospective study

Background and Purpose: Given the evolution of neoadjuvant therapy (NAT) for breast cancer, this study aimed to analyze trends in NAT regimens over time and patients' pathological responses, tumor stages, and subtypes. Materials and Methods: Data were analyzed for 548 patients with cT1-4N0-3M0 breast cancer who received NAT at Shandong Cancer Hospital between 2011 and 2022. The 12-year study period was divided into six 2-year periods termed P1 to P6. Results: From P1 to P6, the proportion of stage II patients treated with NAT increased from 6.4% to 33.8% compared with same-stage operable breast cancer (r = 0.228, P < 0.001), while the proportion of the full-course group increased from 50.0% to 99.0% (r = 0.354, P < 0.001). The pathologic complete remission (pCR) rate in the full-course group increased from 30.8% to 54.6% (r = 0.248, P < 0.001). In the full-course human epidermal growth factor receptor-2 positive (HER2+) group, the proportion of chemotherapy combined with inhibition therapy increased from 33.3% to 100% (r = 0.530, P < 0.001). Furthermore, dual inhibition therapy increased from 0 to 98.9%. The proportion of the nonanthracycline group (dual inhibition) increased from 56.0% at P5 to 76.6% at P6 (r = 0.190, P = 0.042). In the full-course Triple-Negative Breast Cancer (TNBC) group, the proportion of platinum therapy increased from 0 to 41.9% (r = 0.324, P < 0.001) and immune drugs increased from 0 to 53.2% (r = 0.500, P < 0.001). Conclusion: Overall, the results indicate an increasing proportion of patients receiving NAT therapy over time. Furthermore, there were increases in HER2 + patients receiving inhibition therapy (especially dual inhibition) and TNBC patients receiving platinum and immune therapy as part of NAT. Notably, these changes were associated with improved outcomes.