Histological grading in a large series of advanced stage ovarian carcinomas by three widely used grading systems: consistent lack of prognostic significance. A translational research subprotocol of a prospective randomized phase III study (AGO-OVAR 3 protocol).
While there is no doubt that histologic grading is applicable in early stage ovarian carcinoma, it is still in controversial discussion concerning advanced stage ovarian carcinoma. It was the aim of this study to assess the three most widely used grading systems for ovarian carcinoma in terms of prognostic significance, concordance rates, and reproducibility in a large number of advanced stage ovarian carcinomas of all types after standardized chemotherapy. Representative hematoxylin and eosin slides from 334 cases of stage IIB-IV ovarian carcinoma (prospective randomized, multi-center, phase III study) were used. The first round was grading of all cases according to FIGO, GOG, and Silverberg by one author. The second round (after 1 year) was 30 randomly selected cases graded by three authors. None of the three grading systems was prognostically significant (FIGO p = 0.38; GOG p = 0.70; Silverberg p = 0.92). The concordance rates between the three systems were as follows: FIGO/GOG 95.5%, kappa = 0.929; Silverberg/FIGO 69.9%, kappa = 0.533; Silverberg/GOG 66.8%, kappa = 0,481. Grading of advanced stage ovarian carcinomas was of no value for estimation of prognosis in this homogeneously treated patient group. Alternative methods should be defined, which might help to separate patients with high risk of tumor progression from others with low risk.