Further evaluation of reproducibility and prognostic value of histologic typing and grading in FIGO stage I ovarian cancer patients without systemic locoregional adjuvant treatment

In order to analyse the reproducibility and prognostic value of histologic typing and different methods of histologic grading, 102 hematoxylin and eosin stained slides of primary FIGO stage I ovarian cancers of the common epithelial types were evaluated. Patients were treated by surgery only. Histologic typing was done using the FIGO criteria and overall total agreement was 61%. Survival was not statistically significant (P-value range: 0.31-0.66). For grading, three different methods were used: (a) the 'intuitive' method; (b) the FIGO method; and (c) the so-called Pathology Research and Practice (PRP) method, which is based on invasion, architecture and nuclear atypia. The best intra- and interobserver results were obtained with the PRP criteria (interobserver agreement rate: 84.3%, k 0.67; intraobserver agreement rate: 87.3%, k 0.76). Univariate survival analyses showed significant differences between grades for all methods and observers. Results of the PRP method were clearly better than for the FIGO method (PRP, Mantel-Cox range 6.70-24.52, P-value range 0.07-