背景：以前的单中心研究表明，使用两个原发性肿瘤块进行HER2评估（双重块HER2评估）可能是一种有效且实用的方法，可以克服异质性的不利影响并获得胃癌（GC）中的HER2阳性率。这项多中心前瞻性临床试验（NCT02843412）被启动，以验证其价值和通用性。
方法：共有来自中国8家医院的3806名初级GCs参与者被纳入研究。选择两个原发性肿瘤块，并在组织学评估后记录为块1和块2。HER2(4B5)兔单克隆抗体用于免疫组织化学(IHC)分析。
结果：在所有患者中，双重区块评估的HER2IHC阳性（3+）率（9.4％）高于单块评估（区块1：7.8％，第2组：7.8%）（P<0.001）。与单块评估相比，双块评估将阳性率提高了约20%。同样，HER2模棱两可（2+）率在双重阻滞评估中增加（25.8%），高于单块评估(块1:20.3%，第2组：20.9%）（P<0.001）。相反，双重阻滞评估显示HER2阴性（0/1+）率（64.8%）低于单一阻滞评估（block1：71.9%，第2组：71.3%)(P<0.001)。这些发现也在个别医院得到证实。
结论：双重阻断HER2评估可有效提高GC切除标本中HER2IHC阳性率。我们建议在GC的常规临床实践中推广双重阻断HER2评估。
背景：ClinicalTrials.gov，NCT02843412。2016年7月1日注册-回顾性注册。
BACKGROUND: Former single center studies indicated that HER2 assessment with two primary tumor blocks (dual block HER2 assessment) could be an efficient and practical approach to overcome the adverse impact of heterogeneity and acquire a HER2 positive rate in gastric cancer (GC). This multicenter prospective clinical trial (NCT02843412) was launched to verify its value and generality.
METHODS: A total of 3806 participants with primary GCs have been enrolled from 8 hospitals in
China. Two primary tumor blocks were selected and recorded as block 1 and block 2 after histological evaluation. An HER2 (4B5) rabbit monoclonal antibody was used for the immunohistochemistry (IHC) analysis.
RESULTS: In total patients, HER2 IHC positive (3+) rate with dual block assessment (9.4%) was higher than that with single block assessment (block 1: 7.8%, block 2: 7.8%) (P < 0.001). Compared with single-block assessment, dual-block assessment increased the positive rate by approximate 20%. Similarly, HER2 equivocal (2+) rate was increased in dual block assessment (25.8%), which was higher than that in single block assessment (block 1: 20.3%, block 2: 20.9%) (P < 0.001). Conversely, dual block assessment demonstrated a lower HER2 negative (0/1+) rate (64.8%) than single block assessment (block1: 71.9%, block 2: 71.3%) (P < 0.001). These findings were also confirmed in individual hospitals.
CONCLUSIONS: Dual block HER2 assessment effectively increased HER2 IHC positive rate in resected specimens of GC. We recommended dual block HER2 assessment be promoted in routine clinical practice in GC.
BACKGROUND: ClinicalTrials.gov, NCT02843412 . Registered 1 July 2016 - Retrospectively registered.
