Albert Einstein College of Medicine, Bronx, NY.
University of Texas Southwestern Medical Center, Dallas, TX.
Am J Surg Pathol. 2020 Oct;44(10):1381-1388. doi: 10.1097/PAS.0000000000001510.
The eighth edition of the American Joint Committee on Cancer (AJCC) Staging Manual attempts to address ambiguity in the pT category assignment for colon cancer from prior editions. Despite modifications, the distinction between the pT3 and pT4a categories continues to be a source of diagnostic confusion. In this study, we assessed interobserver agreement among pathologists from different institutions in the application of AJCC eighth edition criteria for categorizing deeply invasive colonic adenocarcinomas. We identified morphologic patterns that produce diagnostic confusion. We assessed 47 colon cancers that closely approached the serosal surface. Six pathologists with interest in gastrointestinal pathology and 4 focused in other subspecialties classified each case as pT3 or pT4a, based on examination of low-magnification and high-magnification images of the most deeply invasive area. Interobserver agreement was assessed using Fleiss' κ. Cases displayed 3 morphologic patterns at the advancing tumor edge, namely, (1) continuous invasion through an inflammatory focus, (2) pushing border, and (3) infiltrative glands and cell clusters with serosal reaction. Gastrointestinal pathologists achieved slight (κ=0.21) or moderate (κ=0.46) and (κ=0.51) agreement in each category, whereas agreement among nongastrointestinal pathologist was fair (0.31) and (0.39), or moderate (0.57) for each category, respectively. In 10 (21%) cases, the distinction between pT3 and pT4a would have changed the overall clinical stage. We conclude that histologic criteria for serosal penetration is a persistent source of diagnostic ambiguity for gastrointestinal and general pathologists in the pT categorization of colon cancers. Clarification of these criteria will help ensure uniform reporting of pathologic and clinical stage.
第八版美国癌症联合委员会（AJCC）分期手册试图解决前几版结肠癌 pT 分类中存在的模糊性。尽管进行了修改，但 pT3 和 pT4a 类别的区分仍然是诊断混淆的一个来源。在这项研究中，我们评估了来自不同机构的病理学家在应用 AJCC 第八版标准对深度浸润性结肠腺癌进行分类时的观察者间一致性。我们确定了导致诊断混淆的形态学模式。我们评估了 47 例接近浆膜表面的结肠癌。6 名对胃肠病理学感兴趣的病理学家和 4 名专注于其他亚专科的病理学家根据对最深处浸润区的低倍和高倍图像的检查，将每个病例分类为 pT3 或 pT4a。使用 Fleiss' κ评估观察者间一致性。在肿瘤前缘的推进处，病例显示出 3 种形态模式，分别为（1）通过炎症焦点连续浸润，（2）推挤边界，和（3）浆膜反应的浸润性腺体和细胞簇。胃肠病理学家在每个类别中分别达到轻微（κ=0.21）或中度（κ=0.46）和（κ=0.51）的一致性，而非胃肠病理学家的一致性分别为公平（0.31）和（0.39）或中度（0.57）。在 10 例（21%）病例中，pT3 和 pT4a 的区分将改变整体临床分期。我们的结论是，浆膜穿透的组织学标准是胃肠和普通病理学家在结肠癌 pT 分类中诊断混淆的一个持续来源。澄清这些标准将有助于确保病理和临床分期的统一报告。
