Background: Male breast cancer (MBC) is a rare disease, and the potential influence of low expression of human epidermal growth factor receptor 2 (HER2 low) remains unexplored. Methods: In this prospective cohort study, we evaluated 870 patients treated for MBC between May 2009 and June 2023 to assess HER2 low status and its prognostic implications. Results: With a median follow-up of 43 months (range 1–175 months), 659 eligible patients were categorized into three groups based on HER2 status: 501 (76%) HER2 low, 81 (12.3%) HER2 zero, and 77 (11.7%) HER2 positive. HER2 positivity correlated with younger age, higher proliferation index, non-specific type histology, lymphovascular invasion (LVSI), and low differentiation grade. Notably, all these parameters were equally distributed between the HER2 zero and HER2 low groups. Additionally, HER2 positivity was significantly associated with increased occurrences of regional and distant lymph nodes and pulmonary metastases. However, no statistically significant difference was observed between HER2 zero and HER2 low. Disease-free and overall survival showed no significant disparities between the groups. Conclusions: Our findings suggest that HER2 low status is frequently detected in MBC. Despite this, HER2 low did not correlate with clinical and pathological parameters, nor did it impact patients’ survival.
背景：男性乳腺癌（MBC）是一种罕见疾病，人表皮生长因子受体2低表达（HER2低）的潜在影响尚未明确。方法：在这项前瞻性队列研究中，我们评估了2009年5月至2023年6月期间接受治疗的870例MBC患者，以分析HER2低表达状态及其预后意义。结果：中位随访时间为43个月（范围1-175个月），659例符合条件患者根据HER2状态分为三组：501例（76%）为HER2低表达，81例（12.3%）为HER2零表达，77例（11.7%）为HER2阳性。HER2阳性与年轻年龄、高增殖指数、非特殊类型组织学、淋巴血管侵犯（LVSI）及低分化等级显著相关。值得注意的是，这些参数在HER2零表达组与HER2低表达组间呈均衡分布。此外，HER2阳性与区域/远处淋巴结转移及肺转移发生率增加显著相关，但HER2零表达与HER2低表达组间未观察到统计学显著差异。无病生存期和总生存期在各组间均无显著差异。结论：本研究提示HER2低表达状态在MBC中较为常见，但其与临床病理参数无显著相关性，亦未对患者生存期产生影响。
Prognostic Impact of HER2 Low Status in Male Breast Cancer: Prospective Cohort Analysis
肿瘤(癌症)患者之家