Comparison of the usefulness between a new universal grading system for epithelial ovarian cancer and the FIGO grading system

Abstract Objective The aim of this study was to compare the usefulness of a new universal grading system for ovarian cancer proposed by Shimizu et al. (Cancer 82 (1998), 893; Gynecol. Oncol. 70 (1998), 2) with that of the FIGO grading system as a prognostic factor of ovarian cancer. Methods We reviewed all paraffin-embedded tissues of epithelial ovarian cancer obtained from 130 women who underwent initial treatment including primary surgery in our hospital between January 1990 and December 2000. The scores of the specimens were obtained according to both the universal grading system and the FIGO grading system. Results Both the FIGO grading system and the universal grading system worked as significant prognostic indicators. Patients with Grades 1 and 3 of the universal grading system had high and low 5-year survival rates, respectively, compared to those of the FIGO grading system. Inconsistencies in histologic grade between the FIGO and universal grading systems were observed in 22 patients. The positive rate of lymph node metastasis in patients with Grade 3 of the universal grading system was significantly high compared to those of the FIGO grading system ( P = 0.03). Patients with Grade 3 of the universal grading system with residual tumor of not less than 2 cm in diameter were observed more frequently than those of the FIGO grading system. Conclusion The universal grading system was superior to the FIGO grading system in terms of the prediction of malignancies such as the potential of lymph node metastasis and invasion and the adaptability to clear cell cancer.