Endometrial cancer is a cancer that develops in the lining of the uterus, also known as the endometrium. The uterus is a pear-shaped organ of the female reproductive system where fetal growth and development occurs.
The uterus is made up of three layers: the endometrium, myometrium, and perimetrium (mucus layer protecting the uterus). The endometrium is the inner lining of the uterus, and is the layer that grows thick and sheds when fertilisation does not occur. This occurs monthly in a process known as menstruation. Cancers that develop in the endometrium are much more common, and are called endometrial cancers.
The myometrium is the muscular, middle layer that makes up most of the uterus. It is responsible for holding the structure of the uterus, expanding to enable fetal growth, and inducing uterine contractions during childbirth. Cancers of the myometrium, also known as uterine sarcomas, are considered to be very rare. For more information on uterine sarcomas, please refer to the Rare Cancers Australia Uterine Sarcoma page.
Endometrial cancers are generally diagnosed in women over 50, however, it can affect almost anyone with a uterus – including women, teenagers, transgender men, non-binary individuals, and intersex people - at any age.
Types of Endometrial Cancer
There are several types of endometrial cancers, which can be classified by their cellular appearance under the microscope, and whether the tumour is linked to excess production of the hormone oestrogen.
Type 1 Endometrial Cancers
Type one endometrial cancers are the most common type, and are linked to excess oestrogen production in the body. Oestrogen is one of the main female sex hormones that is responsible for puberty, menstruation, pregnancy, bone strength, and other functions. Excess oestrogen production can cause a variety of health problems; however, type one endometrial cancers rarely metastasise and are often slow growing.
Most type one endometrial cancers are adenocarcinomas (cancers arising from mucus-producing glands in organs), and are often referred to as endometrial adenocarcinomas.
Endometrioid Adenocarcinomas
Endometrioid adenocarcinomas are the most common subtype of endometrial cancers. These cancers are often diagnosed early, and often have a good prognosis. The different types of endometrioid adenocarcinoma includes:
- Adenocarcinoma with squamous differentiation.
- Adenoacanthoma.
- Adenosquamous carcinoma (also known as mixed cell endometrioid adenocarcinomas).
- Ciliated carcinomas.
- Secretory carcinoma.
- Villoglandular adenocarcinoma.
Type 2 Endometrial Cancers
Type two endometrial cancers are a rare type that is not linked to oestrogen production. These cancers are more likely to metastasise, and may not have as good of a prognosis as type one endometrial cancers.
There are several subtypes of type two endometrial cancers, including:
- Clear cell carcinoma.
- Grade III endometrioid cancer.
- Papillary serous carcinoma.
- Undifferentiated carcinoma.
- Uterine carcinosarcomas (also known as malignant mixed Müllerian tumours).
Mesonephric Adenocarcinomas
Mesonephric adenocarcinomas are a very rare subtype of endometrial cancers. These types of tumours have a variety of growth patterns, and are often misdiagnosed as other endometrial cancer subtypes. Because of how rare these tumours are, it is unclear whether they are linked to oestrogen, and therefore whether or not it would be classified as a type one or type two endometrial cancer.
Mesonephric adenocarcinomas are often aggressive, and may not have as good of a prognosis as other types of endometrial cancer.
Treatment
Treatment for endometrial cancer may make it difficult to become pregnant. If fertility is important to you, discuss your options with your doctor prior to the commencement of treatment.
If endometrial cancer is detected, it will be staged and graded based on size, metastasis and how the cancer cells look under the microscope. Staging and grading helps your doctors determine the best treatment for you.
Cancers can be staged using the TNM staging system:
- T (tumour) indicates the size and depth of the tumour.
- N (nodes) indicates whether the cancer has spread to nearby lymph nodes.
- M (metastasis) indicates whether the cancer has spread to other parts of the body.
This system can also be used in combination with a numerical value, from stage 0 – IV:
- Stage 0: this stage describes cancer cells in the place of origin (or ‘in situ’) that have not spread to nearby tissue.
- Stage I: cancer cells have begun to spread to nearby tissue. It is not deeply embedded into nearby tissue and has not spread to lymph nodes. This stage is also known as early-stage cancer.
- Stage II: cancer cells have grown deeper into nearby tissue. Lymph nodes may or may not be affected. This is also known as localised cancer.
- Stage III: the cancer has become larger and has grown deeper into nearby tissue. Lymph nodes are generally affected at this stage. This is also classified as localised cancer.
- Stage IV: the cancer has spread to other tissues and organs in the body. This is also known as advanced or metastatic cancer.
Cancers can also be graded based on the rate of growth and how likely they are to spread:
- Grade I: cancer cells present as slightly abnormal and are usually slow growing. This is also known as a low-grade tumour.
- Grade II: cancer cells present as abnormal and grow faster than grade I cancers. This is also known as an intermediate-grade tumour.
- Grade III: cancer cells present as very abnormal and grow quickly. This is also known as a high-grade tumour.
Once your tumour has been staged and graded, your doctor may recommend genetic testing, which analyses your tumour DNA and can help determine which treatment has the greatest chance of success. They will then discuss the most appropriate course of treatment for you.
Treatment is dependent on several factors, including location, stage of disease and overall health.
Treatment options for endometrial cancer may include:
- Surgery, potentially including:
- Total hysterectomy (removal of the uterus).
- Radical hysterectomy (complete removal of the cervix, uterus, and soft tissue surrounding the cervix and upper part of the vagina).
- Bilateral salpingo-oophorectomy (removal of both ovaries and fallopian tubes).
- Trachelectomy (removal of part or all of the cervix).
- Radiation therapy.
- Chemotherapy.
- Hormone therapy.
- Clinical trials.
- Palliative care.
For more information on treatment options, please refer to the Rare Cancers Australia treatment options page.
Risk factors
The biggest risk factor for endometrial cancer is age. Women over 50 and post-menopausal women are the most at risk.
Other risk factors include:
- Being overweight/obese.
- Family history of uterine, ovarian or bowel cancers.
- Never having been pregnant.
- Any medical condition that changes the balance of female hormones.
- Longer period of menstruation (having a period before 12 or menstruation after the age of 55).
- Certain hormone replacement therapies.
Not everyone with these risk factors will develop the disease, and some people who have the disease may have none of these risk factors. See your general practitioner (GP) if you are concerned.
Early symptoms
The most common symptom of endometrial cancer is unusual vaginal bleeding. This may include:
- Changes in your period.
- Heavier periods.
- Bleeding in between periods.
- Constant bleeding.
- Bleeding after menopause.
Some less common symptoms include:
- Smelly or watery vaginal discharge.
- Abdominal/pelvic pain.
- Unexplained weight loss.
- Changes in bowel habits.
- Painful sex and urination.
Not everyone with the symptoms above will have cancer, but see your GP if you are concerned.
Diagnosis/diagnosing
If your doctor suspects you have an endometrial cancer, they will order a range of diagnostic tests to confirm the diagnosis, and refer you to a specialist for treatment.
Pelvic examination
The doctor will inspect the abdomen for any swelling or masses, followed by your genitalia. The doctor will then insert two fingers into your vagina while simultaneously pressing on your abdomen with their other hand to feel your uterus and ovaries. Following this, the doctor may use a device called a speculum into your vagina, which will separate the vaginal walls and allow viewing of your vaginal canal and cervix for any visible abnormalities. You many request a family member, friend or nurse to be present during this exam.
Imaging & blood tests
The doctor will take images of your body using magnetic resonance imaging (MRI), a computed tomography scan (CT scan), transvaginal ultrasound, and/or positron emission tomography (PET scan), depending on where is is suspected the cancer is. The doctor may also look at other parts of the body and look for signs of metastasis. Additionally, a blood test may be taken to assess your overall health and help guide treatment decisions.
Endometrial biopsy
This type of biopsy can be done in a specialist’s office and can be done without anesthesia. In this procedure, a long, thin plastic tube (pipelle) is inserted into your vagina and through the cervix to reach the uterus. Cells are then gently extracted from the uterine lining, which will be sent to a laboratory for analysis. This procedure only takes a few minutes, but may cause some discomfort similar to period cramps.
Hysteroscopy and biopsy
If the results of the endometrial biopsy are unclear, your doctor may request another biopsy to be performed during a hysteroscopy. This procedure involves inserting a thin, flexible tube with a tiny light and camera (hysteroscope) into your vagina and through the cervix to reach the uterus. A specialist is then able to examine the endometrium for any abnormalities. To take a biopsy, an additional procedure called a dilation and curettage (D&C) may be performed, where your doctor dilates your cervix using surgical instruments and extracts some endometrial tissue for analysis. Both procedures are performed as a day surgery in a hospital under general anesthetic, and may cause some cramping and light bleeding for several days after.
Prognosis (Certain factors affect the prognosis and treatment options)
While it is not possible to predict the exact course of the disease, your doctor may be able to give you a general idea based on stage, rate/depth of tumour growth, susceptibility to treatment, age, overall fitness and medical history. Generally, early-stage endometrial cancers have good prognosis and survival rates. However, if the cancer is advanced and has spread, the prognosis may not be as good and there may be a higher risk of cancer recurrence.
References
Some references are to overseas websites. There may be references to drugs and clinical trials that are not available here in Australia.