Cáncer de endometrio

¿Qué es el cáncer de endometrio?

El cáncer del endometrio, o cáncer uterino, es principalmente un adenocarcinoma que surge del revestimiento del útero y es un tumor dependiente de estrógenos. Esto es distinto del carcinoma del cuello uterino, que es un carcinoma de células escamosas. El cáncer del cuerpo del útero podría incluir sarcoma miometrial.

Tipos de cáncer endometrial

La gran mayoría de los cánceres del endometrio (80%) son adenocarcinomas. Pueden ser indiferenciados.

Hay dos tipos principales de cáncer de endometrio, que corresponden a los endometrioides dependientes de estrógenos (tipo 1) y a los carcinomas no endometrioides independientes de estrógenos (tipo 2).¹

¿Quiénes desarrollan cáncer de endometrio? (Epidemiología)

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

Factores de riesgo del cáncer de endometrio

Los períodos prolongados de estrógeno no contrarrestado son el principal factor de riesgo. Cuando el estrógeno no es modificado por los efectos de la progesterona, se denomina 'estrógeno no contrarrestado'.

Esto puede ocurrir como resultado de la medicación o en ciclos anovulatorios donde el cuerpo lúteo no madura y no secreta progesterona. El diagnóstico histológico puede ser difícil ya que la hiperplasia endometrial gruesa puede parecer un carcinoma bien diferenciado.

Los factores de riesgo para el cáncer de endometrio incluyen: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.

Síntomas del cáncer de endometrio

Historia⁴

The classic symptom of endometrial cancer is sangrado posmenopáusico (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 orientación 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.

Investigación del cáncer de endometrio

Ecografía transvaginal (TVUS)

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.

El grosor medio del endometrio en mujeres posmenopáusicas es mucho más delgado que en mujeres premenopáusicas. El engrosamiento del endometrio puede indicar la presencia de una patología. En general, cuanto más grueso es el endometrio, mayor es la probabilidad de una patología importante, es decir, la presencia de cáncer endometrial.

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.

Además, los patrones endometriales malignos y benignos a menudo pueden determinarse mediante TVUS, lo que puede ayudar en el diagnóstico.

Biopsia endometrial

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.

Estadificación del cáncer de endometrio

Se requiere una histerectomía abdominal total con salpingooforectomía bilateral tanto como tratamiento primario como para el propósito de estadificación.

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.

Tratamiento y manejo del cáncer endometrial

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

Recurrencia

• La recurrencia puede responder a la radioterapia. La radioterapia radical para la recurrencia local es efectiva en más de la mitad de los casos.

• El tratamiento estándar de la recurrencia vaginal es la radioterapia.

• El tratamiento sistémico de la enfermedad metastásica y recurrente puede involucrar terapia endocrina o quimioterapia citotóxica.

Pronóstico del cáncer endometrial²

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.