Cancer de l'endomètre

Qu'est-ce que le cancer de l'endomètre ?

Le cancer de l'endomètre, ou cancer de l'utérus, est principalement un adénocarcinome provenant de la muqueuse de l'utérus et est une tumeur dépendante des œstrogènes. Cela se distingue du carcinome du col de l'utérus qui est un carcinome épidermoïde. Le cancer du corps de l'utérus pourrait inclure le sarcome myométrial.

Types de cancer de l'endomètre

La grande majorité des cancers de l'endomètre (80%) sont des adénocarcinomes. Ils peuvent être indifférenciés.

Il existe deux principaux types de cancer de l'endomètre, correspondant aux carcinomes endométrioïdes dépendants des œstrogènes (type 1) et aux carcinomes non endométrioïdes indépendants des œstrogènes (type 2).¹

Qui est touché par le cancer de l'endomètre ? (Épidémiologie)

Women aged 75 - 79 make up the group with the highest incidence of endometrial cancer in the UK. Endometrial cancer is the fourth most common cancer in women in the UK, with around 10,185 new cases per year, around one-third of which are preventable.²

Facteurs de risque du cancer de l'endomètre

Les périodes prolongées d'œstrogènes non opposés sont le principal facteur de risque. Lorsque l'œstrogène n'est pas modifié par les effets de la progestérone, on parle d'œstrogène non opposé.'

Cela peut se produire à la suite d'un traitement médicamenteux ou lors de cycles anovulatoires où le corps jaune ne mûrit pas et ne sécrète pas de progestérone. Le diagnostic histologique peut être difficile car une hyperplasie endométriale importante peut ressembler à un carcinome bien différencié.

Les facteurs de risque pour le cancer de l'endomètre incluent :³

• Being nulliparous.

• Medical conditions such as polyendocrine metabolic ovarian syndrome (previously known as polycystic ovarian syndrome) which predispose to anovulatory cycles.

• Younger menarche or older menopause.

• Obesity and diabetes - adipose tissue contains oestrogen and it is estimated that 34% of cases of endometrial cancer in the UK are caused by obesity or being overweight. There is a link to diabetes but this may largely be explained by the links between diabetes and obesity.

• Atypical endometrial hyperplasia, which may progress to endometrial cancer and shares its risk factors. 8.2%).

• Genetic conditions such as Lynch syndrome.

• The use of tamoxifen for the treatment of breast cancer.

• Unopposed oestrogen given as hormone replacement therapy (HRT) - women with a uterus should always be given a progestogen when they take HRT.

• Protective factors include use of combined hormonal contraception, and a possible link to physical activity and drinking coffee.

Symptômes du cancer de l'endomètre

Historique⁴

The classic symptom of endometrial cancer is saignement postménopausique (SPM); the National Institute for Health and Care Excellence (NICE) guidance on suspected cancer says that women with unexplained post-menopausal bleeding that cannot be attributed to HRT be referred on a suspected cancer pathway. In their section on endometrial cancer, NICE also advise an urgent direct access ultrasound for women who are 55 or over and have the following:

• Unexplained vaginal discharge:

  • For the first time or

  • With thrombocytosis or

  • With haematuria.

• Visible haematuria:

  • With a low haemoglobin or

  • With thrombocytosis or

  • With high blood glucose levels.

Women who take continuous combined HRT have a risk of endometrial cancer which is significantly lower than that of the general population, and bleeding in this cohort should not be referred on the suspected cancer pathway. Instead, the woman's risk of endometrial cancer should be assessed using the flowchart in the British Menopause Society's directives on unscheduled bleeding on HRT⁵ and the appropriate action taken. Depending on the risk factors, this may include a transvaginal ultrasound scan, an urgent suspected cancer pathway referral, or optimising the woman's HRT.

Anyone referred on the urgent suspected cancer pathway should have cancer diagnosed or ruled out within 28 days - this target has replaced the previous one of being seen within two weeks.

Examen

Unless the disease is well advanced there is unlikely to be any physical abnormality, but examination is always useful - an abnormality of the cervix or genitourinary syndrome of the menopause may be found to be the sole cause, or a contributor to, any unusual bleeding.

If the woman has not had a cervical smear in the appropriate period since her last one, and is aged 64 or under, this should be done when she is seen. This is however a screening test and further investigation or referral should not be delayed pending the smear result.

Enquête sur le cancer de l'endomètre

Échographie transvaginale (ETV)

TVUS scan is the usual first-line procedure to identify which women with PMB are at higher risk of endometrial cancer. In most cases, an urgent suspected cancer pathway referral done for PMB will lead to a 'one-stop shop' clinic where a scan is done and the woman is seen with the result.

L'épaisseur moyenne de l'endomètre chez les femmes postménopausées est beaucoup plus mince que chez les femmes préménopausées. L'épaississement de l'endomètre peut indiquer la présence d'une pathologie. En général, plus l'endomètre est épais, plus la probabilité de pathologie importante est élevée - c'est-à-dire la présence d'un cancer de l'endomètre.

TVUS using a 3-mm cut-off has high sensitivity for detecting endometrial cancer and can identify women with PMB who are highly unlikely to have endometrial cancer, thereby avoiding more invasive endometrial biopsy. Some centres use 4 mm or even 5 mm as a cut-off for endometrial biopsy.

De plus, les motifs endométriaux malins et bénins peuvent souvent être déterminés par TVUS, ce qui peut aider au diagnostic.

Biopsie de l'endomètre

A definitive diagnosis in PMB is made by histology. A sample is usually obtained by endometrial biopsy taken during an outpatient hysteroscopy. All methods of sampling the endometrium will miss some cancers.

Stadification du cancer de l'endomètre

L'hystérectomie abdominale totale avec salpingo-ovariectomie bilatérale est nécessaire à la fois comme traitement principal et pour le stade de la maladie.

In brief, the staging of endometrial cancer is as follows. More details can be found in the relevant guidance from 2023:⁶

• Stage 1 - confined to the body of the uterus.

• Stage 2 - extension to the cervical stroma.

• Stage 3 - local or regional spread outside the uterus.

• Stage 4 - local spread to the bladder or rectal mucosa. metastasis to the extrapelvic peritoneum or more distantly.

Traitement et gestion du cancer de l'endomètre

Treatment options depend upon the endometrial cancer stage and may include surgery, radiotherapy or chemotherapy.

Récurrence

• La récidive peut répondre à la radiothérapie. La radiothérapie radicale pour la récidive locale est efficace dans plus de la moitié des cas.

• Le traitement standard de la récidive vaginale est la radiothérapie.

• Le traitement systémique des maladies métastatiques et récidivantes peut impliquer une thérapie endocrinienne ou une chimiothérapie cytotoxique.

Pronostic du cancer de l'endomètre²

Overall ten-year survival in the UK is 71.7%; this varies with age, increasing to 80.1% for those aged under 45 and dropping to 54.8% for those aged 75 or over.

Those women who are diagnosed early have a far better prognosis. One-year survival is 92.4% for those diagnosed at stage 1 but only 46.9% for those diagnosed at stage 4.