Currently, patients with stage II-III breast cancer still accounts for a large population in China, and neoadjuvant therapy is considered the standard treatment for them. The pathological complete response (pCR) rate takes for an indicator for regimens efficacy, and the achievement of pCR after neoadjuvant chemotherapy is associated with favorable outcomes including disease-free survival and overall survival.
HER2+ breast cancer represents an invasive and poor prognosis subtype, and the efficacy of neoadjuvant therapy for these patients has been greatly augmented by the addition of trastuzumab. However, more than 50% of HER2+ breast cancer patients treated with trastuzumab combined neoadjuvant chemotherapy cannot achieve pCR, even experience primary drug resistance and rapid disease progression. Therefore, to explore the genomic features of the population that benefited from trastuzumab combined with chemotherapy is of great significance for personalized treatment of HER2+ breast cancer, aiming to avoid overtreatment and identify clinically actionable mutations for future therapy instructions.
