FIGO Classification of Endometrial Cancer

Staging System

The International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial cancer emphasizes myometrial invasion depth, cervical stromal involvement, and lymph node metastases, with the 2009 version being the current standard, although a 2023 update has been introduced 1, 2.

The FIGO staging system transitioned from clinical to surgical staging in 1988, requiring systematic pelvic and para-aortic lymphadenectomy for complete staging 1, 3.
In 2009, FIGO published a revised staging system that simplified several categories and better reflected the natural history of endometrial cancer 1, 2, 4.

Stage IA is characterized by no myometrial invasion or invasion to less than half of the myometrium 1, 2.
Stage IB is characterized by invasion equal to or more than half of the myometrium 1, 2.
Stage II involves tumor invasion of cervical stroma but does not extend beyond the uterus 1, 2.
Stage IIIA involves tumor invasion of the serosa of the corpus uteri and/or adnexae 1, 2.
Stage IIIB involves vaginal and/or parametrial involvement 1, 2.
Stage IIIC involves metastasis to pelvic and/or para-aortic lymph nodes, with IIIC1 being positive pelvic lymph nodes and IIIC2 being positive para-aortic lymph nodes with or without pelvic nodes 1, 2, 5.

Preoperative evaluation should include chest X-ray, clinical and gynecological examination, transvaginal ultrasound, blood counts, liver and renal function profiles 1, 3.
Contrast-enhanced dynamic MRI is the best tool to assess cervical involvement when suspected 1, 5, 6.
Surgical staging components include total hysterectomy with bilateral salpingo-oophorectomy, assessment of depth of myometrial invasion, and systematic pelvic and para-aortic lymphadenectomy 2, 4.

Approximately 75% of patients present with Stage I disease, which can be subdivided into low-risk (Stage IA, grade 1-2, endometrioid histology, no LVSI), intermediate-risk (Stage IB, grade 1-2, endometrioid histology), and high-risk (Stage IB grade 3, deep myometrial invasion with LVSI, or non-endometrioid histology) categories 1, 6, 5.

Lymphadenectomy controversy: while systematic pelvic lymphadenectomy provides prognostic information, randomized trials showed no improvement in disease-free or overall survival for routine lymphadenectomy in Stage I disease 1, 4.
Sentinel lymph node mapping is an acceptable alternative to complete lymphadenectomy, with a sensitivity of 97.2% and negative predictive value of 99.6% when using indocyanine green and following NCCN surgical algorithm 5.