Real-world, single-center experience on the outcomes of neoadjuvant chemotherapy and trastuzumab alone or in combination with pertuzumab in human epidermal growth factor receptor-2 breast cancer patients.

Abstract

e12589 Background: Neoadjuvant chemotherapy (NACT) is the standard of care for early-stage breast cancer (BC). Human epidermal growth factor receptor 2 (HER2) positive disease constitutes a large proportion of BC patients, and HER2 overexpression is associated with poor prognosis. The introduction of HER2+ targeted therapies, such as trastuzumab and pertuzumab, has resulted in improved outcomes in HER2+ BC. NACT in combination with HER2 targeted therapies aims at achieving pathological complete response (pCR) and an improved survival rates. Methods: We performed a retrospective review of HER2+ BC patients who were treated at Medanta – The Medicity Hospital, Gurugram, Haryana, India, between 2011 and 2021. A total of 108 HER2+ BC patients who received NACT with platinum, anthracycline or taxane-based regimens, along with trastuzumab alone or in combination with pertuzumab, were included. Results: Of 108 enrolled patients, 66 and 42 patients received neoadjuvant single-blockade (trastuzumab) and dual-blockade (trastuzumab and pertuzumab) anti-HER2 therapy, respectively. The majority of patients were aged < 60 years. The patient populations were comparable in terms of clinical stage, hormone receptor status, histopathology category [Invasive ductal carcinoma (IDC) being most common] and Ki67 status for both groups. All patients had IHC3+/FISH+ HER2 expression. No significant (p = 0.896) difference was observed for breast conserving surgery between the groups. A higher pCR rate after surgery was reported in the dual-blockade versus single-blockade group (50% vs. 39.2%; p = 0.271). The median follow-up duration was 21.9 and 15.2 months in the single-blockade and dual-blockade groups, respectively. For dual- vs. single- blockade groups, the 1-year OS rates were 100% each, and 3-year OS rates were 100% vs. 98.48%. For dual- vs. single- blockade groups, the 1-year DFS rates were 100% vs. 95.45%, and 3-year DFS rates were 92.85% vs. 80.3% respectively. Conclusions: Neoadjuvant chemotherapy with dual HER2-blockade had higher pCR and survival rates compared with the single HER2-blockade strategy in HER2 positive breast cancer. [Table: see text]