Interobserver agreement for tumour type, grade of differentiation and stage in endometrial carcinomas

The histopathologic evaluation plays a major role in subdividing endometrial carcinomas into treatment groups. We have evaluated the interobserver agreement regarding tumour type, grade of differentiation, stage and stage I low and high risk cases. A total of 177 cases of endometrial carcinoma in which a hysterectomy and a bilateral salpingo-oophorectomy were performed, were reviewed by three examiners. A variety of features including tumour type, architectural grade, nuclear grade, FIGO grade, and spread/metastases were recorded, and the FIGO stage was determined. Using two different definitions low and high risk groups in stage I tumours were separated. A kappa value was calculated for each of the various parameters. The current study showed a good strength of agreement for tumour type, myometrial invasion, spread/metastases, and FIGO stage (kappa 0.62-1.00). For two of the examiners good agreement was found as to architectural grade (kappa 0.71) while the kappa value for nuclear grade was lower (0.56). As nuclear grading is included in the revised FIGO recommendation a precise definition of nuclear atypia is needed. In stage I tumours very good agreement was demonstrated as to the defined low and high risk group (Kappa 0.64-0.86).