2014 FIGO staging for ovarian, fallopian tube and peritoneal cancer.

Cancer staging is a core principle in understanding the severity of patients' clinical condition, predicting the outcome, and planning adequate treatment. Staging is necessary for explaining epidemiologic changes, defining the disease at presentation, and evaluating the overall impact of new therapies. In essence, it assigns patients to prognostic groups that require specific treatments. The steps of staging typically begin by establishing the histopathologic diagnosis, according to the tumor cell type, and assessing prognosis based on extent of disease and other known prognostic parameters. Recently, the presence of variousmolecular genetic alterations has been used in the establishment of prognosis and even staging classification in some tumors but gynecologic cancers have continued to rely on physical, radiographic and surgical findings. This editorial is written to make the readership aware of the recent changes that have been made by the International Federation of Gynecology and Obstetrics (FIGO) in the staging classification of ovarian cancer and the reasoning behind those changes [1]. Even if the FIGO Committee on Gynecologic Oncology utilized the best evidence currently available, this is always a somewhat subjective process. Furthermore, one needs to be aware that FIGO is an international organization that must take into account the needs of women with gynecologic cancers throughout the world, and not just those from countries that are resource rich. The first FIGO ovarian cancer staging was published in 1973 in Volume 15 of the FIGO Annual Report. Since that time there have been two other changes including this one in 1988 and 2013. Ovarian cancer is not one disease. Several distinct tumors with unique clinical andpathological featuresmay arise in the ovary. Approximately 90% of ovarian cancers are carcinomas (malignant epithelial tumors) and, based on histopathology, immunohistochemistry, and molecular genetic analysis, at least 5 main types are currently distinguished: high-grade serous carcinoma (HGSC [70%]); endometrioid carcinoma (EC [10%]); clear-cell carcinoma (CCC [10%]); mucinous carcinoma (MC [3%]); and low-grade serous carcinoma (LGSC [less than 5%] [2]). These tumor types (which account for 98% of ovarian carcinomas) can be reproducibly diagnosed by lightmicroscopy and are essentially different diseases, as indicated by differences in epidemiologic and genetic risk factors; precursor lesions; ways of spread; andmolecular changes during oncogenesis, response to chemotherapy, and outcome [3] Much less frequent are malignant germ cell tumors (dysgerminomas, yolk sac tumors, and immature teratomas [3% of ovarian cancers]) and potentially malignant sex cord-stromal tumors (1%– 2%, mainly granulosa cell tumors). The biomarker expression profile within a given histotype is consistent across stages. In short, ovarian cancers differ primarily based on histotype. Primary fallopian tube cancer and primary peritoneal cancer are rare malignancies but share many clinical andmorphologic similarities with