What is gestational trophoblastic disease?

Gestational trophoblastic disease (GTD) is the name for abnormal cells or tumours that grow from the tissue that forms in the womb during pregnancy. 

GTD is very rare. It can be non cancerous (benign) or cancerous (malignant).

There are different types of GTD. These include:

• molar pregnancy (complete or partial)
• invasive mole or persistent trophoblastic disease (PTD)
• choriocarcinoma
• atypical placental site nodule (APSN)
• placental site trophoblastic tumour (PSTT)
• epithelioid trophoblastic tumour (ETT)

Although GTD starts in the womb, it behaves very differently from cancer of the womb. It is also treated differently.

If you are looking for information about womb cancer (also known as uterine or endometrial cancer) go to our womb cancer section.

How gestational trophoblastic diseases develop

Gestation means pregnancy. Trophoblasts are the cells that form during the normal development of a baby. 

Usually, after a sperm fertilises an egg, new cells grow within the womb to form an embryo. As the embryo grows, its cells start to specialise. Some cells start to form the baby (foetus) and others form the placenta. The placenta protects and nourishes the baby during pregnancy.

The first layer of cells that develops into the placenta is called the trophoblast. The trophoblast produces tiny, finger-like, outgrowths known as villi. These villi attach the placenta to the lining of the womb. 

Molar pregnancy 

There is a problem when the sperm fertilises the egg. The foetus either doesn’t develop at all, or it partly forms but can't grow normally. The villi may swell up and grow in clusters, a bit like bunches of grapes. Unfortunately a molar pregnancy cannot develop into a healthy baby.

Molar pregnancy is the most common type of GTD and can be either partial or complete. They are not cancerous – they are benign. But rarely, a molar pregnancy can become cancerous and can spread to other parts of the body. 

Invasive mole and choriocarcinoma

Some trophoblastic cells grow abnormally and develop into a tumour. These tumours are cancerous and can sometimes spread outside the womb.

An invasive mole is a cancer that can form in the womb after a molar pregnancy. It is also called persistent trophoblastic disease (PTD). 

Choriocarcinoma is a very rare cancer that can occur after a normal pregnancy, a molar pregnancy, a miscarriage or a termination of pregnancy (abortion). 

Placental site trophoblastic tumours (PSTT) and epithelioid trophoblastic tumours (ETT) 

These cancers can occur several months, or even years after a pregnancy. They can happen after any type of pregnancy, including molar pregnancy, miscarriage or a full term normal pregnancy. They develop in the area where the placenta joined the lining of the womb (uterus). They can grow into the muscle layer of the womb and can sometimes spread to other parts of the body. 

Other terms used to describe gestational trophoblastic disease (GTD)

The medical descriptions for gestational trophoblastic disease are all quite long and can sound complicated. There are many terms that may be used for these types of tumours including:

• gestational trophoblastic tumour (GTT)
• trophoblastic disease
• gestational tumour
• gestational trophoblastic neoplasia (GTN)
• molar pregnancy (partial or complete)
• invasive mole
• persistent trophoblastic disease (PTD)
• choriocarcinoma
• atypical placental site nodule (APSN)
• placental site trophoblastic tumour (PSTT)
• epithelioid trophoblastic tumour (ETT)

Treatment

Treatment for all types of GTD is very successful and most women are cured. 

You can read more about treatment in the section or page about each type of GTD.

Research

Doctors are always looking to improve treatments for GTD, and reduce side effects. As part of your treatment, your doctor may ask you to take part in a clinical trial. This might be to test a new treatment or to look at different combinations of existing treatments.