The Fallopian Tube Origin and Primary Site Assignment in Extrauterine High-grade Serous Carcinoma: Findings of a Survey of Pathologists and Clinicians

Accumulating recent evidence suggests that the majority of extrauterine high-grade serous carcinomas (HGSCs) do not arise from the ovary as historically accepted but from the distal, fimbrial end of the fallopian tube from a precursor known as serous tubal intraepithelial carcinoma. There has been variable acceptance of this evidence among pathologists and clinicians dealing with ovarian cancer and this has resulted in wide variation in the assignment of primary site between different institutions when HGSC involves >1 anatomic site. This has obvious implications for cancer epidemiology, registration, and entry into clinical trials. We undertook a survey of members of several national and international gynecologic pathology and clinical cancer societies with a view to ascertaining the degree of acceptance of the fallopian tube origin of extrauterine HGSC and to explore various aspects regarding site assignment, pathologic sampling, diagnosis, FIGO staging, and reporting of these neoplasms. The results indicate wide acceptance among both pathologists and clinicians of the fallopian tube theory of origin of HGSC (86% pathologists, 92% clinicians), although there is significant variation regarding the perceived importance of assigning a primary site given the limited prognostic and therapeutic significance. Interestingly, clinicians feel it is more important to assign a primary site than pathologists (71% vs. 49%). The survey also indicates widespread acceptance of recently proposed criteria for site assignment in extrauterine HGSC.