[Expert consensus on diagnosis and treatment of advanced non-small cell lung cancer with HER-2 alterations (2025 edition)].

Mutations in the human epidermal growth factor receptor 2 (HER-2) gene are recognized as significant but relatively rare driver alterations in non-small cell lung cancer (NSCLC). These mutations predominantly manifest as gene mutation, amplification, and protein overexpression, with an estimated prevalence from 2.8% to 15.4% among NSCLC patients in China. Research indicates that HER-2 mutations, particularly exon 20 insertions (ex20ins), are strongly correlated with aggressive tumor biology, poor prognosis, and limited responsiveness to immunotherapy, thereby exhibiting characteristics of "cold tumors". Overexpression and amplification of HER-2 are also indicative of a heightened risk of chemotherapy resistance and unfavorable survival outcomes, suggesting a distinct molecular subtype with unique biological behaviors. In recent years, novel antibody-drug conjugates (ADCs), particularly trastuzumab deruxtecan (T-DXd), have demonstrated groundbreaking efficacy in HER-2-mutant advanced NSCLC patients. These ADCs have shown significant clinical benefits, including high objective response rates and progression-free survival advantages, making T-DXd the first targeted therapy approved for this patient population globally. Additionally, ADCs have exhibited therapeutic potential in patients with HER-2 overexpression, thus broadening the scope of their indications. To standardize the clinical diagnosis and treatment of HER-2 variant NSCLC, the Chinese Anti-cancer Association convened multidisciplinary experts from oncology, pulmonology, thoracic surgery, pathology, and molecular diagnostics to develop this consensus based on the latest evidences from both domestic and international studies, coupled with China's clinical practice experience. This consensus focuses on the molecular characteristics, clinical significance, diagnostic strategies, treatment options, and safety management of HER-2 alterations, addressing ten critical clinical questions in a systematic manner. It is recommended that HER-2 status be routinely tested at initial diagnosis, disease progression, or recurrence in NSCLC. Mutation detection should prioritize next-generation sequencing (NGS), while protein overexpression may be assessed using immunohistochemistry (IHC) standards for gastric cancer. Fluorescence in situ hybridization (FISH) is recommended for detecting HER-2 amplification. Regarding treatment, for HER-2-mutant patients, first-line therapy may involve chemotherapy with or without immune checkpoint inhibitors (ICIs), similar to treatment approaches for driver-gene negative populations. Upon failure of first-line treatment, trastuzumab deruxtecan, may be considered as alternative therapeutic options. For patients with HER-2 overexpression, ADCs should be considered after failure of standard systemic therapy. However, the management of HER-2 amplification remains insufficiently supported by evidence, necessitating a cautious, individualized approach. The consensus also includes detailed recommendations for screening and managing adverse effects associated with ADCs, such as interstitial lung disease (ILD), emphasizing the crucial role of safety management in ensuring treatment efficacy. The publication of this consensus aims to drive the standardization of molecular diagnosis and treatment pathways for HER-2 variant NSCLC, improve clinical outcomes and quality of life for patients, and facilitate the implementation of personalized precision treatment strategies.