Karamchandani Dipti M, Gonzalez Raul S, Lee Hwajeong, Westerhoff Maria, Cox Brian, Pai Rish K
UT Southwestern Medical Center, Dallas, TX, USA.
Emory University, Atlanta, GA, USA.
Histopathology. 2025 Jun;86(7):1101-1111. doi: 10.1111/his.15415. Epub 2025 Jan 28.
The current American Joint Committee on Cancer (AJCC) staging manual and the College of American Pathologists (CAP) colorectal carcinoma (CRC) protocol specify use of a four-tiered grading system (i.e. grades 1-4; well-differentiated-undifferentiated) for CRC, based on percentage of gland formation. The World Health Organization (WHO) 5th edition grades CRC into low-grade (well- and moderately differentiated) and high-grade (poorly and undifferentiated), based on the least differentiated component. We studied interobserver agreement and practice patterns among pathologists when grading CRC by these two grading systems.
Five gastrointestinal pathologists reviewed 100 scanned CRC slides and graded the tumour on each slide, per provided criteria in (a) WHO 5th edition book, (b) AJCC manual/CAP CRC protocol and (c) their clinical practice. A questionnaire for grading selected CRC subtypes was also provided. Statistical analysis was performed using Pearson's χ test and Fleiss multi-rater kappa analyses. Overall, agreement among the five reviewers when grading via WHO and AJCC criteria for low-grade and high-grade CRC was moderate (κ = 0.568, P < 0.001) and good (κ = 0.611, P < 0.001), respectively. All reviewers graded significantly more tumours as high-grade when using WHO (median = 46) versus AJCC/CAP criteria (median = 20).
Interobserver agreement was higher using the AJCC grading criteria as a two-tiered system. Significantly more tumours were called high-grade using the WHO criteria. This raises concerns regarding upgrading tumours, as well as potential differences in grading tumours among pathologists worldwide, based on regional preferred grading systems. Synchronisation of these two grading systems is necessary for uniform grading of CRCs throughout institutions.
当前美国癌症联合委员会（AJCC）分期手册和美国病理学家学会（CAP）结直肠癌（CRC）协议规定，根据腺体形成百分比，对CRC采用四级分级系统（即1 - 4级；高分化 - 未分化）。世界卫生组织（WHO）第5版根据分化最差的成分将CRC分为低级别（高分化和中分化）和高级别（低分化和未分化）。我们研究了病理学家在使用这两种分级系统对CRC进行分级时的观察者间一致性和实践模式。
五位胃肠病理学家审阅了100张扫描的CRC切片，并根据（a）WHO第5版书籍、（b）AJCC手册/CAP CRC协议和（c）他们的临床实践中提供的标准，对每张切片上的肿瘤进行分级。还提供了一份用于对选定CRC亚型进行分级的问卷。使用Pearson卡方检验和Fleiss多评分者kappa分析进行统计分析。总体而言，五位审阅者在通过WHO和AJCC标准对低级别和高级别CRC进行分级时，一致性分别为中等（κ = 0.568，P < 0.001）和良好（κ = 0.611，P < 0.001）。与AJCC/CAP标准（中位数 = 20）相比，所有审阅者在使用WHO标准时将更多肿瘤分级为高级别（中位数 = 46）。
使用AJCC分级标准作为两级系统时，观察者间一致性更高。使用WHO标准时，被称为高级别的肿瘤明显更多。这引发了对肿瘤升级的担忧，以及基于地区偏好的分级系统，全球病理学家在肿瘤分级方面可能存在的差异。为了在各机构中对CRC进行统一分级，这两种分级系统的同步是必要的。
