Placental site trophoblastic tumour and epithelioid trophoblastic tumour
Placental site trophoblastic tumours (PSTTs) and epithelioid trophoblastic tumours (ETTs) are cancers that happen after pregnancy. They are extremely rare and are slow growing.
What are placental site trophoblastic tumours and epithelioid trophoblastic tumours?
These tumours are part of a group of conditions called gestational trophoblastic disease (GTD). GTD is the name for abnormal cells or tumours that grow from the tissue that forms in the 
during pregnancy. Less than 1 in 100 (less than 1%) of GTDs are placental site trophoblastic tumours or epithelioid trophoblastic tumours.
In PSTT and ETT the tumour develops from the cells that grow to form the . The cells are called trophoblast cells. They can happen after any type of pregnancy. This includes molar pregnancy, miscarriage, abortion, or a full term pregnancy. They can occur several months, or even years afterwards.
These tumours develop in the area where the placenta joined the lining of the womb (uterus). They are generally slow growing, but can spread beyond the womb.
Atypical placental site nodule (APSN)
Very rarely, tiny amounts of tissue from the placenta stay in the womb after pregnancy. This can grow abnormally. This is called an atypical placental site nodule (APSN).
APSN is not cancerous, but about 10 to 15 out of 100 (about 10 to 15%) may develop into PSTT or ETT.
If you are diagnosed with APSN you are monitored by one of the specialist GTD centres.
Symptoms of PSTT and ETT
The main symptom of PSTT and ETT is irregular bleeding from the vagina. In some women this follows a loss of periods (amenorrhoea).
Diagnosing PSTT and ETT
If you have irregular vaginal bleeding or your periods have stopped your doctor will refer you for tests. You might have the following tests.
Blood test
Women with PSTT and ETT might have raised levels of a hormone called human chorionic gonadotrophin (hCG) in their blood. This hormone may be produced by the PSTT/ETT cells.
Ultrasound
An ultrasound scan might show abnormal areas in the lining of the womb. A special type of scan called a Doppler ultrasound uses colour to show up body structures. The Doppler scan can show that there are more blood vessels than usual in the area of the tumour.
CT or MRI scan
If you have APSN, PSTT or ETT, or your doctors think you have it, you might need to have a or . These are used to help with diagnosis.
Surgery to sample the womb lining
You might have an operation called a dilation and curettage (D and C) under general anaesthetic in hospital. Once you are asleep, the surgeon opens up (dilates) the entrance to the womb (cervix) and takes a sample of any abnormal areas.
The doctor uses a small instrument called a curette to scrape the lining of the womb. They send the tissue they have removed to the laboratory. Under the microscope a pathologist can tell if the cells are an APSN, PSTT or ETT.
Treatment for PSTT and ETT
Surgery
The main treatment is usually surgery if the tumour is only in the womb. Most women have their womb removed (a hysterectomy). After surgery the womb is sent to the laboratory for checking. This is to:
- confirm the diagnosis of PSTT or ETT
- do tests to decide if you need any more treatment
Some women might have surgery to remove spread elsewhere in the body. For example, an operation to remove an area of spread to the lungs.
Chemotherapy and drug treatments
Chemotherapy is a type of anti cancer drug treatment. It works by killing cancer cells. It is a systemic treatment which means it works throughout your body.
You usually have chemotherapy if:
- the PSTT or ETT has spread to another part of your body, such as the area around the womb or the lungs
- the PSTT or ETT is diagnosed over 4 years after the end of your pregnancy
Chemotherapy treatment usually involves a combination of drugs. The drugs used include:
-
etoposide, cisplatin, methotrexate and actinomycin-D (EP-EMA)
-
paclitaxel, cisplatin (TP)
-
paclitaxel, etoposide (TE)
Immunotherapy
Immunotherapy uses our immune system to fight cancer. It works by helping the immune system recognise and attack cancer cells.
Some women might have treatment with an immunotherapy drug called pembrolizumab.
Your healthcare team will discuss with you what treatment you need and how long your treatment will last.
Follow up after treatment
After treatment your specialist will monitor you closely. You have tests to check how well the treatment has worked and to monitor your progress. These can include:
- blood and urine tests
- ultrasound scans
- MRI scans
- CT scans
Your specialist team will continue to monitor you for life. They can explain in detail what your follow up will involve.
Help and support
This can be a worrying and difficult time for you, your family, and friends. The specialist GTD centres have support groups for people affected by any form of GTD. If there isn’t a group near you, you may be able to join one by video. This means you can still talk to others and share experiences from home. Your local centre can tell you more about this.
