The new classifications of ovarian, fallopian tube, and primary peritoneal cancer and their clinical implications

The roles of histologic characterization and staging are to provide reproducible metrics for cancer classification with which to direct the most appropriate clinical care and to yield the most stable reliable system to allow both prospective and retrospective data analysis. Both the histologic and staging classifications of malignant ovarian/tubal/peritoneal cancers have recently changed. The World Health Organization sponsored a review and reclassification of the pathology of cancers of the ovaries, fallopian tubes, and peritoneum, and published these updates in 2014. In so doing, they codified the two-tiered grading system that has been in use in serous ovarian cancers for nearly a decade. In parallel, FIGO reviewed and updated the surgical staging system, applied to all histotypes of ovarian, tubal, and peritoneal cancers, also published in 2014. In both cases, the changes made are meant to encompass a better understanding of disease, but both have important merits and drawbacks. Changes in staging complicate analysis of retrospective data against current data. Though in some aspects controversial, the changes overall are meant to represent a better biologic understanding of disease that we hope will lead to an improvement in patient care and directed therapy.