Endometrial carcinoma: 10 years of TCGA (the cancer genome atlas): A critical reappraisal with comments on FIGO 2023 staging

The Cancer Genome Atlas (TCGA) Research Network described 4 molecular subgroups of endometrial carcinomas with different outcome: 1) POLE ultramutated endometrioid carcinomas which have an indolent behavior; 2) microsatellite instability hypermutated endometrioid carcinomas associated with intermediate prognosis; 3) copy-number low endometrioid carcinomas also with intermediate prognosis; and 4) copy-number high predominantly serous (non-endometrioid) but also serous-like endometrioid carcinomas, almost always carrying TP53 mutations, with poor clinical outcome. After 10 years of comprehensive analysis, it appears that the only real contribution of TCGA to the clinical management of these patients would be limited to the infrequent high-grade, early-stage endometrioid carcinomas with POLE exonuclease domain mutations, as these patients could benefit from a de-escalating treatment; knowledge about the other three subgroups has not changed significantly. The copy-number low (or non-specific genetic profile) which is the most frequent subgroup, is a mixture subgroup where investigators are currently trying to establish prognostic markers; for example, unexpected variations in a relatively small percentage of cases (i.e., CTNNB1 mutated or p53 aberrant low-grade and low-stage endometrioid carcinomas associated with unfavorable prognosis). On the other hand, TCGA has underlined that a small number of grade 3 endometrioid carcinomas, all TP53 mutated, overlap with copy-number high serous carcinomas. Recently, TCGA molecular subgroups have been integrated into the 2023 International Federation of Gynecology and Obstetrics (FIGO) staging classification which incorporates other non-anatomic parameters like histotype, tumor grade, and lymphovascular space invasion. The result is a complicated and non-intuitive classification that makes its clinical application difficult and does not facilitate correspondence with the 2009 FIGO staging.