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

Abstract

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.

Data set for reporting of ovary, fallopian tube and primary peritoneal carcinoma: recommendations from the International Collaboration on Cancer Reporting (ICCR)

“…In the case of designating the site of origin of HGSC, the recommendations have been recently published. 24 In the case of TRG, the panel has endorsed a CRS that is reproducible and easy to use and has been shown to be of prognostic relevance. 119 The expert panel was also able to exclude an outdated and unvalidated data item (LVI).…”

“…Based on a recent publication, recommendations for assigning the site of origin of extra-uterine HGSC are provided in the following section. 24 Using these criteria, assignment of primary site is no longer based on the site of the greatest volume/size of tumour, but in the presence of STIC or invasive HGSC in the tubal mucosa, a fallopian tube origin is rendered, although as discussed later (section on 'Serous tubal intraepithelial carcinoma'), fallopian tube mucosal involvement by uterine or non-gynaecological primary tumours can occur and mimic STIC. Application of these criteria will be important in ensuring consistency between different pathologists in assigning the site of origin of HGSC with obvious important implications for cancer registration and other parameters.…”

“…Undoubtedly, there will be evolution over time in our ability to accurately assign the primary tumour site but the following are intended as practical guidelines for handling cases at the present time ( Figure 1). 24 (1) The fallopian tubes, or at least their fimbrial ends, should be totally sampled in all the cases of HGSC by a SEE-FIM-like protocol 19 26 and only after complete examination of the fallopian tubes (including the nonfimbrial portions) has excluded the presence of STIC or a small tubal HGSC…”

Primary Fallopian Tube Carcinoma

“…The ovaries or endometrium are either normal or contain a tumour that is smaller than the tumour in the tube. Recently, Singh et al (24), proposed an approach to the pathological assignment of primary site in highgrade serous tubal, ovarian, and peritoneal carcinoma. According to Singh, the identification of tumour inside the fallopian tubes, even in the presence of larger tumours in other localizations, supports the diagnosis of PFTC (24).…”

Serous Tubal Intraepithelial Carcinoma (STIC)-like Lesions Arising in Ovarian Serous Cystadenofibroma

“…There is now convincing evidence that the majority of ''ovarian'' HGSCs arise from the epithelium of the distal fimbrial portion of the fallopian tube from a precursor lesion known as serous tubal intraepithelial carcinoma (STIC) (4)(5)(6)(7)(8)(9)(10)(11). We report 2 cases of lesions morphologically identical to STIC (hereafter referred to as STIC-like lesions) arising from the benign ciliated epithelium of ovarian serous cystadenofibromas.…”