Assignment of primary site in high-grade serous tubal, ovarian and peritoneal carcinoma: a proposal

The revised FIGO 2013 staging for carcinomas of the ovary, fallopian tube and peritoneum has introduced a single system for tumours originating at these sites. The system requires pathologists to assign a primary site (ovary, tube or peritoneum), but does not provide guidance to aid this assignment. This is particularly problematic in cases of advanced-stage (stage II or greater) high-grade serous carcinoma (HGSC), where there is commonly involvement of two or more sites by tumour, and practice among pathologists in determining where a tumour has arisen varies widely. This has significant implications for recording of tumour incidence and mortality, data collection by cancer registries, and entry into clinical trials. We propose guidelines for assigning the primary site of HGSC based on careful macroscopic and histological assessment. The use of these guidelines, in conjunction with the new FIGO staging system, is intended to act as an impetus to promote debate and provide a uniform and consistent approach in assigning primary tumour site which will facilitate comparison of data between centres.