TOWARD THE DEVELOPMENT OF A UNIVERSAL GRADING SYSTEM FOR OVARIAN EPITHELIAL CARCINOMA - I - PROGNOSTIC-SIGNIFICANCE OF HISTOPATHOLOGIC FEATURES - PROBLEMS INVOLVED IN THE ARCHITECTURAL GRADING SYSTEM

Objective. Because there is no universally accepted grading system for ovarian epithelial carcinoma, we attempted to compare the prognostic utility of the individual components used in some systems-both archite ctural and cytologic features, as well as mitotic activity and histolo gic tumor type-to determine which of these components fit best with su rvival. Methods. We studied 461 patients with invasive ovarian carcino ma who had uniform treatment, complete clinical data including staging and follow-up, and slides available for review. Each tumor was assign ed a histologic subtype, architectural grade (based on whether the pre dominant pattern was glandular, papillary or solid), nuclear grade, mi totic count, and FIGO grade (based on the system for endometrial carci noma). These features were compared with each other and with tumor sta ge and survival. Results. The architectural grade, nuclear grade, and mitotic count were independent variables both in stage I/II and stage III/IV disease. Each of them correlated with survival for most combina tions of histologic type and stage. By multivariate analysis, in stage I/II cancer, nuclear grade and architectural grade were significantly correlated with survival, mitotic count showed only a trend, and FIGO grade did not correlate. In stage III/IV disease, nuclear grade, arch itectural grade 3, and mitotic count were significant, and FIGO grade was not. Conclusion. The new architectural grading system proposed wor ked better than the FIGO system in this study. Furthermore, it could b e applied to all histologic subtypes of carcinoma. The nuclear grade a nd mitotic count were also independent of each other, correlated with survival, and could be utilized for all histologic types. These data s upport the development of a grading system which combines these archit ectural, nuclear, and mitotic features and can be applied regardless o f the histologic type of carcinoma, modeled after the Nottingham syste m for grading of breast carcinoma. (C) 1998 Academic Press.