FIGO Staging of Endometrial Adenocarcinoma: A Critical Review and Proposal

To the Editor: I read with great interest the review article published in the journal by Zaino1 and commend his effort in compiling a succinct summary of grading and staging endometrioid-type adenocarcinoma highlighting several important contentious issues. Staging Stage 1 Stage 1 disease is a challenging category and the likelihood of death from the tumor is markedly increased for women with deeply invasive tumors1. The first challenge that comes to mind is: How deep is deep? We tend to have high interobserver reproducibility if the tumor is a few millimeters from the serosa but significantly less so if the tumor is invading into 55% of the myometrial thickness. A possible suggestion is to consider it a 2-tier stage 1: Stage 1A: the tumor is confined to the endometrium with or without superficial invasion of the myometrium. Stage 1B: when the tumor invades into the myometrium to a distance of, for example, more than 3 HPF (or other agreed but well-defined distance) from the endo/myometrial junction in the examined blocks except when there is involvement of adenomyosis by carcinoma. Endometrioid-type adenocarcinomas vary considerably from one area to another and the worst feature could be missed out without adequate sampling. Stage 2 In the absence of specific features to clarify the controversy regarding cervical involvement in stage 2, it is perhaps useful to adopt the already existing criteria that are used to define the transition of cervical glandular intra-epithelial neoplasia into endocervical adenocarcinoma to separate endometrioid-type adenocarcinoma stage 2A from 2B. The extent of cervical sampling is another point that perhaps requires consideration and consensus. Do we base our assessment on the standard anterior and posterior cervical blocks or should it be based on sampling the entire cervix? It has been reported2 that there is no significant difference between the 2 standard blocks of the cervix and sampling the entire cervix, but the jury is still out to confirm this in a bigger study. Stage 3 Positive peritoneal washings in the absence of other pelvic organs' involvement perhaps are the most subjective of all the controversial issues. Usually, the pathologists prefer to overestimate rather than underestimate their assessment. This, together with the absence of defined diagnostic criteria, makes this parameter the least reproducible. Perhaps if we consider establishing clear-cut criteria, for example, the abnormal looking cells have to be positive for Ber ep4, as a starting point might achieve more reproducibility. Otherwise, all other markers are also positive in reactive mesothelial cells, which could even look more worrying than any other malignant tumor. Spread to the adnexa can also be difficult to assess. For example, in our experience, we had 2 cases in which a cluster of tumor cells with surrounding reactive macrophages and stromal cells was seen detached in the fallopian tube lumen. No doubt that there are other examples in which it is difficult to categorize the tumor in a particular stage or substage. Grading Like anything else in histopathology, the assessment relies on the extent of sampling and we accept that there is a limitation to the process when we reach a point of diminished return. However, in grading endometrioid-type adenocarcinoma we are adding more bias to an already subjective grading technique by introducing the assessment of the percentage of solid component and also the extent of atypia. It has been reported that the latter should involve the majority of the tumors.1 What is the definition of majority? What if there was only one block of a 50-mm tumor to be assessed? In this case, is the presence of 60% atypia of the slides or even 7% solid component of this tumor enough to make it grade 2? How confident and consistent are we in reporting 7% as a solid component? A slightly different, but more reproducible, approach is to have a 3-tier grading system in which grade 1 contains no solid component, grade 2 any solid component up to 50% and grade 3 solid component forming more than 50% of the examined material is a more reproducible system. Sampling To make the criteria of staging and grading meaningful, we need to define what is considered as good sampling representation of the tumor of the examined material. Should we agree that these findings are present in all blocks and the blocks must be taken 1 block per 1 cm of the maximum dimension of the tumor? We need to have a baseline of what is considered as good sampling representation of the tumor; for example, 1 section per 1 cm of the maximum dimension of the tumor is an essential starting point. Most of the studies were done in centers with special interest in this subject and therefore their assessment, evaluation, and sampling tend to be more thorough than some other centers, which might have different views, different interests, or even under various financial pressures to cut down on the cost, which influence their practice by taking a fewer number of blocks. Suha Deen, FRCPath Nottingham University Hospitals Nottingham, UK