Fact-sheet: Endometrial cancer


Updated on 05/09/2026 at 11:23 AM

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Definition

Endometrial cancer is the most common invasive gynecologic malignancy in France.

Two types are classically distinguished:

  • Type 1, hormone-dependent, low-grade G1-G2 endometrioid, favorable prognosis
  • Type 2, non-hormone-dependent, including serous, clear cell, and carcinosarcoma types, unfavorable prognosis

The 2023 FIGO update emphasizes the distinction between non-aggressive (G1-G2 endometrioid) and aggressive (G3 and non-endometrioid types) histologic subtypes.

Clinical features

Primarily affects postmenopausal women: mean age 60 to 70 years.

  • Postmenopausal bleeding: presenting sign in 80% of cases.
  • Risk factors: Obesity (peripheral aromatization of estrogens in adipose tissue), diabetes, nulliparity, late menopause, and Tamoxifen therapy.
  • Genetic syndromes: 5% of cases are related to Lynch syndrome.

Laboratory findings

No specific blood biomarker for diagnosis

Importance of molecular variables integrated into the 2023 FIGO staging:

  • POLE mutations (favorable prognosis)
  • p53 (unfavorable prognosis).

Ultrasound

Transvaginal ultrasound: First-line examination for abnormal bleeding.

Endometrial thickness: The pathologic threshold is classically > 4 mm in postmenopausal women (sensitivity 89-97%). A recent meta-analysis even suggests a 3 mm threshold for a sensitivity of 97.5%.

Signs of malignancy:

  • Heterogeneous echogenic endometrium,
  • irregular contours of the endometrial-myometrial interface,
  • hypervascularity on Doppler.

CT

Abdominopelvic CT is not part of the initial locoregional staging workup, except when MRI is contraindicated.

Staging workup:

  • distant metastases: pulmonary, hepatic
  • lumbo-aortic lymphadenopathy in advanced stages (III and IV) or aggressive histologic types.

MRI

Reference examination for preoperative staging.

Optimized technical protocol

  • Preparation: 4 to 6 hour fasting, moderately full bladder, and administration of an antiperistaltic agent (Glucagon 1 mg IV or IM) to limit bowel motion artifacts.
  • Morphologic sequences: High-resolution T2 in 3 planes (sagittal, oblique axial perpendicular to the long axis of the uterus, and oblique coronal parallel to the uterus).
  • Diffusion-weighted imaging (DWI): Essential (b values of 0, 400, and 800/1000). The cancer shows hyperintensity on b800 and low ADC (threshold of 1.05 × 10⁻³ mm²/s to distinguish from normal tissue).
  • Dynamic contrast-enhanced (DCE) sequence, ideally acquired dynamically. Tumor-to-myometrium contrast is optimal at 2 min 30 s (equilibrium phase) for assessing myometrial invasion.

MRI findings

  • Tumor: Intermediate T2 signal, lower than normal endometrium,
  • Lesser enhancement than the myometrium (80% of cases).
  • Myometrial invasion: Disruption of the junctional zone (T2 dark line).
  • Preservation of a thin, continuous subendometrial enhancing rim excludes invasion.

Nuclear medicine

FDG PET-CT is discussed in cases of suspected advanced stages (III/IV) or type 2 to search for occult metastases. It outperforms MRI for the detection of metastatic lymph nodes (sensitivity 91%, specificity 100%).

Management

  • Histological diagnosis by endometrial biopsy or curettage.
  • Pelvic MRI to assess myometrial and cervical infiltration.
  • Distant staging workup (chest/abdomen/pelvis CT or PET-CT) according to grade and histological type.
  • Discussion at the multidisciplinary tumor board to tailor surgery (lymphadenectomy or sentinel lymph node technique) based on recurrence risk (ESMO).

Classification

The 2023 FIGO classification incorporates histological aggressiveness and molecular data.

Stage I (confined to the uterus):

  • IA1: Non-aggressive, confined to the endometrium. No myometrial invasion.
  • IA2: Non-aggressive, myometrial invasion < 50%.
  • IA3: Non-aggressive, invasion < 50% AND ovarian involvement (low risk).
  • IB: Non-aggressive, myometrial invasion > 50%.
  • IC: Aggressive, confined to the endometrium, without myometrial invasion.

Stage II:

  • IIA: Cervical stromal invasion (non-aggressive).
  • IIB: Substantial lymphovascular space invasion (LVSI).
  • IIC: Aggressive with any myometrial invasion.

Stage III, Local/regional extension:

  • IIIA1: Adnexa (tubes/ovaries).
  • IIIA2: Uterine serosa or subserosa.
  • IIIB1: Vagina or parametria.
  • IIIB2: Pelvic peritoneum.
  • IIIC: Lymph nodes (IIIC1: pelvic; IIIC2: infrarenal para-aortic). Micrometastases (< 2 mm) are designated "i" and macrometastases (> 2 mm) "ii".

Stage IV:

  • IV1: Bladder/rectal involvement
  • IVB: extrapelvic peritoneal metastases
  • IVC: distant metastases including inguinal lymph nodes.

The TNM classification, which is based on the same anatomical criteria as the FIGO classification, has been updated to align with the major 2023 FIGO revisions.

T - Primary tumor (Corresponds to anatomical FIGO stages I, II, and III)

  • T1: Tumor confined to the uterine corpus (FIGO I) T1a (FIGO IA): Invasion of less than 50% of myometrial thickness.
  • IA1: Non-aggressive type, confined to the endometrium (no myometrial invasion).
  • IA2: Non-aggressive type, myometrial invasion < 50%.
  • IA3: Non-aggressive type, invasion < 50% AND limited ovarian involvement (not extending beyond the ovarian capsule).
  • T1b (FIGO IB): Non-aggressive type, myometrial invasion > 50%.
  • T1c (FIGO IC): Aggressive type, confined to the endometrium (without myometrial invasion).
  • T2: Tumor invading the cervical stroma (FIGO II) FIGO IIA: Cervical stromal invasion (non-aggressive type).
  • FIGO IIB: Presence of substantial lymphovascular space invasion (LVSI) (any degree of myometrial invasion).
  • FIGO IIC: Aggressive type with any myometrial invasion.
  • T3: Local or regional extension (FIGO III) T3a (FIGO IIIA): IIIA1: Involvement of the tubes or ovaries (except stage IA3).
  • IIIA2: Involvement of the uterine subserosa or serosa.
  • T3b (FIGO IIIB): IIIB1: Involvement of the vagina or parametria.
  • IIIB2: Involvement of the pelvic peritoneum.

N - Regional lymph node involvement (FIGO IIIC)

The classification now distinguishes micrometastases (< 2 mm) from macrometastases (> 2 mm).

  • N1 (FIGO IIIC1): Metastases in pelvic lymph nodes. IIIC1i: Micrometastases.
  • IIIC1ii: Macrometastases.
  • N2 (FIGO IIIC2): Metastases in infrarenal para-aortic lymph nodes. IIIC2i: Micrometastases.
  • IIIC2ii: Macrometastases.

M - Distant metastases (FIGO IV)

  • FIGO IVA: Invasion of the bladder or bowel mucosa (must be confirmed by endoscopy).
  • M1: Distant metastases FIGO IVB: Peritoneal metastases beyond the pelvis.
  • FIGO IVC: Other distant metastases, including inguinal and supra-renal lymph nodes, or hematogenous metastases (lung, liver, bone, brain).

Molecular integration (Specific to FIGO 2023)

The stage is modified if the molecular profile is known, independently of the anatomical extent in certain cases:

  • Stage IAm (POLE mut): POLE mutation (very favorable prognosis).
  • Stage IICm (p53mut): p53 mutation (unfavorable prognosis), reclassified as aggressive stage.

Differential diagnosis

  • Endometrial polyps: higher ADC, often more intense enhancement.
  • Endometrial hyperplasia: preserved junctional zone on T2.
  • Adenomyosis: thickening of the junctional zone that may mimic tumor invasion (classic pitfall).
  • Submucosal fibroids: very low T2 signal (if fibrous), distorting the cavity without malignant invasion.

Review of sonographic evaluation of normal and pathologic endometrial thickness:

  • First part of the cycle, proliferative phase endometrium: 2 hypoechoic bands on either side of the echogenic linear cavity line
  • thickness: 4-8mm. Nearly nil at the end of menses. Maximum 10mm at the end of the proliferative phase
  • Ovulatory period: target or periovulatory ring appearance
  • Second part of the cycle, secretory phase: the endometrium progressively becomes hyperechoic from the periphery toward the endometrial reflection line
  • +/- premenstrual hematometra, which may give a pseudo-gestational sac appearance
  • thickness: 8-14mm
  • Menstrual period: thin endometrium
  • doubling of the cavity line: hematometra + clots and echogenic mucosal debris
  • Menopause <5mm in the absence of HRT
  • <10mm under HRT
  • If thickness > normal: >=5mm if postmenopausal, otherwise >=16mm. Endometrial hypertrophy simple hypertrophy: globally homogeneous and echogenic mucosa
  • mucosal folds
  • polypoid hypertrophy (mucosal polyp: hyperechoic, oval, 5-20mm)
  • glandular-cystic hypertrophy
  • Endometrial cancer, diffuse or localized form --> MRI
  • If thickness < normal: endometrial atrophy