Distribution and case-fatality ratios by cell-type for ovarian carcinomas: A 22-year series of 562 patients with uniform current histological classification

Ovarian carcinoma is comprised of several different cell types reflecting different clinicopathologic features. Pathologic criteria for distinguishing cell types have evolved, and therefore non-contemporary literature on ovarian cancer may have limited current relevance. A new dualistic model of pathogenesis that distinguishes type I (endometrioid, mucinous, clear cell and low grade serous carcinomas) from type II (high grade serous carcinomas and carcinosarcomas) tumors has become widely accepted.A cohort of 562 patients with invasive ovarian carcinoma from a large community hospital practice was reviewed. Cell type, FIGO stage, mortality and interpathologist diagnostic reproducibility were analyzed.Advanced stage ovarian carcinomas were type II in 86% of cases while low stage tumors were most often type I. Only 1.7% of type II tumors were confirmed to be stage I with comprehensive surgical staging. Type II tumors accounted for 85% of deaths, and clear cell carcinomas, 5% of deaths. Cell type-specific case-fatality ratios for type II tumors were 62% and 79% for high grade serous carcinoma and carcinosarcoma, respectively. For type I tumors, case-fatality ratios were 38%, 36%, 27% and 13% for low grade serous, clear cell, endometrioid and mucinous carcinomas, respectively. The kappa value for diagnostic reproducibility among 3 gynecologic pathologists was 0.83.Current diagnostic criteria confirm that high grade serous carcinoma and carcinosarcoma account for the vast majority (85%) of ovarian cancer deaths. Cell type designation is highly reproducible among gynecologic pathologists. Type II tumors are rarely stage I (<2%) when comprehensively staged by a gynecologic oncologist.