2023 FIGO endometrial cancer stage with molecular classification*

LVSI: lymphovascular space involvement; MMRd: mismatch repair deficiency; NSMP: no specific molecular profile; p53abn: p53 abnormal.

* When feasible, the addition of molecular subtype to the staging criteria allows a better prediction of prognosis in a staging/prognosis scheme. The performance of complete molecular classification (POLEmut, MMRd, NSMP, p53abn) is encouraged in all cases of endometrial cancer for prognostic risk-group stratification and as potential influencing factors of adjuvant or systemic treatment decisions. Molecular subtype assignment can be done on a biopsy, in which case it need not be repeated on the hysterectomy specimen. When performed, these molecular classifications should be recorded in all stages.

• Good prognosis: pathogenic POLE mutation (POLEmut)
• Intermediate prognosis: MMRd/microsatellite instability and NSMP
• Poor prognosis: p53abn

When the molecular classification is known:

• FIGO stages I and II are based on surgical/anatomical and histological findings. In case the molecular classification reveals POLEmut or p53abn status, the FIGO stage is modified in the early stage of the disease. This is depicted in the FIGO stage by the addition of "m" for molecular classification, and a subscript is added to denote POLEmut or p53abn status, as shown below. MMRd or NSMP status do not modify early FIGO stages; however, these molecular classifications should be recorded for the purpose of data collection. When molecular classification reveals MMRd or NSMP, it should be recorded as stage Im_MMRd or stage Im_NSMP and stage IIm_MMRd or stage IIm_NSMP.
• FIGO stages III and IV are based on surgical/anatomical findings. The stage category is not modified by molecular classification; however, the molecular classification should be recorded if known. When the molecular classification is known, it should be recorded as stage IIIm or stage IVm with the appropriate subscript for the purpose of data collection. For example, when molecular classification reveals p53abn, it should be recorded as stage IIIm_p53abn or stage IVm_p53abn.