Efficacy and prognosis of different chemotherapy frameworks in neoadjuvant treatment for HER2-positive breast cancer under targeted therapy：a real-world retrospective observational study

Abstract

Abstract Purpose The optimal neoadjuvant chemotherapy regimen for early-stage human epidermal growth factor receptor 2(HER2)-positive breast cancer in the context of anti-HER2 therapy is unclear. The aim of this study was to compare the effects of anthracycline and non-anthracycline regimens, under different HER2 blocking conditions, on the efficacy and long-term prognosis of neoadjuvant chemotherapy for HER2-positive breast cancer. Methods In this real-world retrospective observational study, 270 patients treated with neoadjuvant therapy for stage II-III HER2-positive breast cancer in our center, were analyzed. All of these patients received neoadjuvant chemotherapy with anthracyclines or non-anthracyclines in the context of anti-HER2 therapy. Results Between 2016 and 2022, 270 patients met the inclusion criteria. The median follow-up time was 36.6 months (range 12.5–85.8 months). Of the 124 patients in the anthracycline group, 60 (48.4%, 95% CI 39.5–57.3) achieved pCR. 84 (57.5%, 95% CI 49.4–65.6) of the 146 patients in the non-anthracycline group achieved pCR (p = 0.133). Under single-target therapy, the pCR in anthracycline group and non-anthracycline group were 44.8% and 53.8%, respectively (P = 0.216). Under dual-target therapy, the pCR rates were 60.7% and 63.6% for both (p = 0.795). In the non-anthracycline treatment group under dual-target therapy, the pCR was 81.8% and 51.5% for platinum-containing and platinum-free regimens, respectively (p = 0.022). It was more pronounced in hormone receptor(HR)-positive patients. Multivariate analysis showed that HR status༈OR: 1.810;95%CI1.090-3.005༛p = 0.022༉, choice of targeted therapy༈OR༚1.883༛95%CI1.072-3.306༛p = 0.028༉and HER2 status༈OR༚4.216༛95%CI1.459-12.188༛p = 0.008༉were independent predictors of pCR. The estimated 3-year DFS rates were 93.5% and 85.9% in the non-anthracycline and anthracycline groups, respectively (p = 0.029). The 3-year OS was 96.1% and 93.3%, respectively (p = 0.118). The 3-year DFS in the non-anthracycline and anthracycline groups of patients with RCB 2 was 94.7% and 76.5%, respectively (p = 0.037). Especially in non-pCR patients treated with dual target therapy, patients treated with non-anthracyclines had better DFS benefit (p = 0.033). Patients who achieved pCR had better DFS (95% vs 85.9%; p = 0.001) and OS (97.2% vs 93.4%; p = 0.013) than those who did not. Conclusion In the neoadjuvant therapy of HER2-positive early-stage breast cancer patients, the use of platinum-containing non-anthracycline chemotherapy in the context of targeted therapy is an effective regimen for improving the long-term prognosis of patients. (particularly the long-term prognosis of non-pCR patients). In particular, patients with HR-positive breast cancer have better benefits under dual-target therapy.