Brown L J, Smeeton N C, Dixon M F
J Clin Pathol. 1985 Feb;38(2):174-9. doi: 10.1136/jcp.38.2.174.
Observer variation in the grading of dysplasia in 100 colorectal adenomas has been analysed by kappa statistics. Intraobserver agreement was only 70% and 67% for the two principal observers, and, as would be expected, interobserver agreement was even lower at 59% and 66%. Although the kappa values were significantly different from chance at the 0.1% level, there were substantial disagreements. When the study was extended to four observers, agreement between observer pairings was considerably worse (as low as 34%), and in four pairings the kappa values did not differ significantly from those expected by chance alone even at the 5% level. In an endeavour to improve agreement we adopted a percentage estimation grading method; but this failed to achieve any improvement when comparing overall grades. The percentage estimates of the two observers, however, showed a highly significant correlation. To identify the cytological features given most weight by the principal observers in assessing dysplasia we undertook morphometry on 30 adenomas using an image analysis computer. The nuclear to cytoplasmic ratio, variation in nuclear area, and variation in nuclear height above the basement membrane showed significant differences between mild, moderate, and severely dysplastic epithelia. While evaluation of these parameters therefore appears to be most important in the subjective interpretation of dysplasia, this study has shown that such evaluation is poorly standardised between observers and poorly reproduced within observers. Our findings of poor agreement in the grading of dysplasia in colorectal adenomas has serious implications for the assessment of dysplasia in inflammatory bowel disease, where the added problem of reactive cellular atypia brings greater complexity to these subjective judgments.
已通过kappa统计分析了100例大肠腺瘤发育异常分级中的观察者变异。两位主要观察者的观察者内一致性分别仅为70%和67%，并且，正如预期的那样，观察者间一致性更低，分别为59%和66%。尽管kappa值在0.1%水平上显著不同于随机概率，但仍存在大量分歧。当研究扩展至四位观察者时，观察者配对之间的一致性更差（低至34%），并且在四组配对中，kappa值即使在5%水平上也与仅由随机概率预期的值无显著差异。为了努力提高一致性，我们采用了百分比估计分级方法；但在比较总体分级时，这未能实现任何改善。然而，两位观察者的百分比估计显示出高度显著的相关性。为了确定主要观察者在评估发育异常时最重视的细胞学特征，我们使用图像分析计算机对30例腺瘤进行了形态测量。核质比、核面积变异以及基底膜上方核高度变异在轻度、中度和重度发育异常上皮之间显示出显著差异。因此，虽然对这些参数的评估在发育异常的主观解释中似乎最为重要，但本研究表明，这种评估在观察者之间的标准化程度很低，在观察者内部的重复性也很差。我们在大肠腺瘤发育异常分级中一致性差的发现对炎症性肠病中发育异常的评估具有严重影响，在炎症性肠病中，反应性细胞异型性这一额外问题给这些主观判断带来了更大的复杂性。
