<i>HER2</i>-Positive Breast Cancer Patients with Pre-Treatment Axillary Involvement or Postmenopausal Status Benefit from Neoadjuvant Rather than Adjuvant Chemotherapy Plus Trastuzumab Regimens

• Main Authors: Enora Laas, Arnaud Bresset, Jean-Guillaume Féron, Claire Le Gal, Lauren Darrigues, Florence Coussy, Beatriz Grandal, Lucie Laot, Jean-Yves Pierga, Fabien Reyal, Anne-Sophie Hamy
• Format: Article
• Language: English
• Published: MDPI AG 2021-01-01
• Series: Cancers
• Subjects: breast cancer; neoadjuvant chemotherapy; adjuvant chemotherapy; <i>HER2</i>-positive tumors
• Online Access: https://www.mdpi.com/2072-6694/13/3/370

Background: No survival benefit has yet been demonstrated for neoadjuvant chemotherapy (NAC) against <i>HER2</i>-positive tumors in patients with early breast cancer (BC). The objective of this study was to compare the prognosis of <i>HER2</i>-positive BC patients treated with NAC to that of patients treated with adjuvant chemotherapy (AC). Materials and methods: We retrospectively analyzed disease-free (DFS) and overall survival (OS) in 202 <i>HER2</i>-positive patients treated with NAC and 701 patients treated with AC. All patients received trastuzumab in addition to chemotherapy. Patient data were weighted by a propensity score to overcome selection bias. Results: After inverse probability of treatment weights (IPTW) adjustment, no difference in DFS (<i>p</i> = 0.3) was found between treatments for the total population. However, after multivariate analysis, an interaction was found between cN status and chemotherapy strategy (IPTW-corrected corrected Hazard ratio cHR = 0.52, 95% CI (0.3–0.9), <i>p</i>_interaction = 0.08) and between menopausal status and chemotherapy (CT) strategy (cHR = 0.35, 95%CI (0.18–0.7)) <i>p</i>_interaction < 0.01). NAC was more beneficial than AC strategy in cN-positive patients and in postmenopausal patients. Moreover, after IPTW adjustment, the multivariate analysis showed that the neoadjuvant strategy conferred a significant OS benefit (cHR = 0.09, 95%CI [0.02–0.35], <i>p</i> < 0.001). Conclusion: In patients with <i>HER2</i>-positive BC, the NAC strategy is more beneficial than the AC strategy, particularly in cN-positive and postmenopausal patients. NAC should be used as a first-line treatment for <i>HER2</i>-positive tumors.