New Views of Ovarian Carcinoma Types: How Will This Change Practice?

Abstract

Ovarian carcinomas are heterogeneous, comprised of five different cell types: high-grade serous, low-grade serous, endometrioid, clear cell, and mucinous carcinoma. High-grade serous carcinoma causes the vast majority of ovarian cancer deaths. This classification correlates with a variety of distinctive clinical, epidemiological, molecular, and behavioral features. This cell type-specific approach is a valuable framework for understanding the biology of ovarian cancer and investigating novel treatment approaches. An alternative, complementary framework is provided by the dualistic model which divides ovarian carcinomas into type I and type II tumors. Type I carcinomas arise from well-characterized precursor lesions (endometriosis and atypical proliferative (borderline) tumors), present in low stage, and have an indolent behavior (endometrioid, mucinous, low-grade serous carcinomas, and most clear cell carcinomas). Type II tumors present in advanced stage and appear to progress rapidly (high-grade serous carcinomas). A body of literature is now converging on a consensus that the majority of high-grade serous carcinomas arise from intraepithelial carcinoma of the fallopian tube. These data form the basis of our new conceptual understanding of “ovarian cancer” and are ultimately hoped to improve treatment and lead to effective screening and prevention strategies.