Gestational trophoblastic disease (GTD)

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

After conception, tissue grows to form part of the placenta (an organ that provides oxygen and nutrients to a developing baby during pregnancy) and surrounds the fertilized egg in the uterus, forming a trophoblast.

In GTD, abnormal changes in the trophoblast cells cause tumors to develop.

Molar pregnancy is the most common type of GTD and is a condition that occurs when the sperm fertilises the egg during conception. It can be either partial or complete. In most cases they are not cancerous but rarely, a molar pregnancy can become cancerous and may spread to other parts of the body.   

What is a complete molar pregnancy? 

A complete molar pregnancy happens when a sperm fertilises an empty egg that contains no chromosomes or genetic material (DNA) from the woman. In a complete molar pregnancy, no parts of a baby form – there is only molar tissue in the womb. Surgery or drug treatment is required to remove the molar tissue. Afterwards, any residual molar tissue usually dies out. However, in around 10-15 out of 100 women (around 10-15%) some molar tissue remains in the deeper tissues of the womb or other parts of the body. This is called an invasive mole. An invasive mole is cancerous and is usually treated with chemotherapy. 

What is a partial molar pregnancy? 

A partial molar pregnancy forms when two sperm fertilise the egg at the same time. There is one set of female chromosomes and two sets of male chromosomes. There may be some fetal tissue within the molar tissue so it may look like there is a baby on an ultrasound scan, but sadly, the foetal tissue cannot develop into a healthy baby due to the chromosome abnormality. Most women with a partial molar pregnancy do not need to have any further treatment after the initial removal of molar tissue from the womb. However, around 1 in 100 women (around 1%) have some remaining abnormal cells in the deeper tissues of the womb or other parts of the body. This is called an invasive mole or Persistent trophoblastic disease (PTD).

Invasive mole, also known as Persistent trophoblastic disease (PTD) is most commonly found in the womb. However, some trophoblastic cells grow abnormally and develop into a tumor. These tumors are cancerous and can sometimes spread outside the womb. Even a very small amount of molar tissue anywhere in the body can grow and cause problems, but it has a very high cure rate. 

A choriocarcinoma is a cancer that happens when cells in the placenta that were part of a molar pregnancy or any other type of pregnancy (full term, miscarriage or ectopic) become cancerous. Choriocarcinoma only happens in about one in every 50,000 pregnancies. A choriocarcinoma can develop some months or even years after pregnancy. It can grow quickly and might cause symptoms within a short period of time and spread to other parts of the body, but it is usually cured by chemotherapy treatment.

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. They can grow into the muscle layer of the womb and can sometimes spread to other parts of the body. 

These are extremely rare tumors comprising 0.2% of all GTD cases. If these cancers are just in the uterus, then treatment is normally a hysterectomy (surgical removal of the womb), possibly followed by chemotherapy.

Some of the symptoms caused by GTD can include: 

• Vaginal bleeding after delivery, miscarriage or abortion that lasts longer than six weeks and shows no signs of stopping 

• An enlarged uterus 

• Pelvic pain or pressure 

• Severe nausea and vomiting 

• High blood pressure with headache and swelling of feet and hands early in pregnancy 

• Anemia, which can be cause fatigue, shortness of breath, dizziness and a fast or irregular heartbeat 

• Overactive thyroid 

If you experience any of these symptoms, you should speak to your doctor. 

Most women can be treated and cured for all types of GTD. However, some women have to endure many rounds of chemotherapy which comes with all the well-known toxic side effects such as infection, hair loss, peripheral neuropathy (nerve damage) and early menopause – which may mean difficulties in conceiving for some women.

CTRT are currently trying to develop ways to avoid the use of toxic multi-drug chemotherapy to treat GTD by running a trial of immunotherapy treatment instead.

Immunotherapy is a better tolerated treatment that helps the immune system fight the disease. It can educate the immune system to attack specific cancer cells and boost immune cells to help them eliminate cancer and has no lasting side effects.

This trial will cost £1.6 million to run and we need your help to raise funds to enable the trial to go ahead. Please click below to read full details about the trial and how you can get involved and donate.