回顾性分析真实世界中HER2低表达乳腺癌的临床病理特征

Clinicopathological features of breast cancer with HER2 low expression:a real-world retrospective study

目的探讨HER2低表达乳腺癌的特征。方法收集北京协和医院2019年4月至2022年7月3422例存档的浸润性乳腺癌患者临床资料,其中包括具有完整新辅助化疗信息的患者136例。所分析的指标包括年龄、雌激素受体和孕激素受体状态、HER2状态、Ki-67阳性指数、组织学分型、肿瘤分化、肿瘤大小及淋巴结转移,以及病理完全缓解(pathologic complete response,pCR)率。结果在未接受新辅助治疗的3286例乳腺癌中,检出免疫组织化学(IHC)0者616例(616/3286,18.7%)、IHC 1+者1047例(1047/3286,31.9%)、IHC 2+者1099例(1099/3286,33.4%)及IHC 3+者524例(524/3286,15.9%)。在IHC 2+组中1070例乳腺癌进行荧光原位杂交(FISH)检测,其中HER2扩增者161例。在本队列中,HER2低表达(IHC 1+和IHC 2+/FISH-)乳腺癌共计1956例。与HER2 IHC 0组相比,HER2低表达好发于50岁以上(P=0.008)、激素受体阳性(P<0.001)、Ki-67阳性指数<35%(P<0.001)及非低分化(P<0.001)的乳腺癌中。而组织学分型、肿瘤大小及淋巴结转移情况等临床病理特征在HER2低表达和HER2 IHC 0组中差异无统计学意义(P>0.05)。新辅助化疗后,HER2低表达组的pCR率低于HER2 IHC 0组(分别为13.3%和23.9%),但差异无统计学意义(P>0.05);尽管按激素受体状态分类,也都观察到HER2低表达组的pCR率略低于HER2 IHC 0组,但差异仍无统计学意义(P>0.05)。结论HER2低表达组乳腺癌的临床病理特征不同于HER2 IHC 0组。准确区分HER2低表达和HER2 IHC 0并探索其是否为一个独立的生物学实体是有必要的。

Objective To investigate the clinical and pathological characteristics of breast cancer with HER2 low expression.Methods The data from 3422 patients with invasive breast cancer which archived in Peking Union Medical College Hospital between April 2019 and July 2022 were retrospectively reviewed.Among them,136 patients were treated with neoadjuvant chemotherapy.The tumor size,histological type,tumor differentiation,lymph node metastasis,Ki-67 index,the status of estrogen receptor,progesterone receptor and HER2 as well as pathological complete response(pCR)rate were collected.Results The HER2 status of 3286 patients without neoadjuvant therapy,616(616/3286,18.7%)score 0,1047(1047/3286,31.9%)score 1+,1099(1099/3286,33.4%)score 2+and 524(524/3286,15.9%)score 3+by immunohistochemistry(IHC).Among the 1070 IHC 2+cases,161 were classified as HER2 positive by reflex fluorescence in situ hybridization(FISH)assay.In our cohort,1956 cases of HER2-low(IHC 1+and IHC 2+/FISH-)breast cancer were identified.Compared to the HER2 IHC 0 group,HER2-low tumors more frequently occurred in patients with hormone receptor(HR)positive(P<0.001),Ki-67 index below 35%(P<0.001),well or moderate differentiation(P<0.001)and over the age of 50(P=0.008).However,there were no significant differences in histological type,tumor size,and lymph node metastasis between HER2-low and HER2 IHC 0 group.For patients who had neoadjuvant therapy,the pCR rate in the patients with HER2-low was lower than those with HER2 IHC 0(13.3%,23.9%),but there was no significant difference.Although HER2-low breast cancers showed a slightly lower pCR rate than HER2 IHC 0 tumors,no remarkable difference was observed between tumors with HER2-low and HER2 IHC 0 regardless of hormone receptor status.Conclusions The clinicopathological features of HER2-low breast cancers are different from those with HER2 IHC 0.It is necessary to accurately distinguish HER2-low breast cancer from HER2 IHC 0 and to reveal whether HER2-low tumor is a distinct biological entity.