Staging of persistent trophoblastic disease (PTD) and choriocarcinoma

The stage of persistent trophoblastic tumour (PTD) or choriocarcinoma means whether the abnormal cells are just in the womb or have spread to other areas of the body.

Staging is important because treatment is decided according to the stage. You will have tests and scans to find the stage.

The FIGO staging system

The staging system used for persistent trophoblastic disease and choriocarcinoma is called the FIGO staging system. This system looks at the stage of disease. It also scores various risk factors to work out which treatment you need.

It uses a numbering system for both the stage and risk factor score.

After removal of a molar pregnancy you have regular blood and urine tests to check the levels of a hormone called human chorionic gonadotrophin (hCG).

If the levels of hCG don't go down this is a sign that abnormal cells are present in the body and you will have tests to find out where the cells are and whether they have spread. 

Your doctor will also do tests if:

• there is evidence of choriocarcinoma in the tissue sample taken during removal of a molar pregnancy
• you have heavy vaginal bleeding and/or severe abdominal pain

The number stages of gestational trophoblastic disease (GTD)

There are 4 main stages. Stage 1 is an early tumour and stage 4 the most advanced.

Stage 1

This is the earliest stage of GTD when the tumour is only in the womb (uterus).

Stage 2

This is when the tumour has spread outside the womb to genital areas nearby, such as the vagina or ovary. It has not spread outside the pelvis.

Stage 3

The GTD has spread to the lungs and may or may not be in the local area around the womb.

Stage 4

The abnormal cells have spread (metastasised) to other parts of the body, such as the liver or brain. 

About risk factors

When you are diagnosed with persistent trophoblastic disease your doctors look at certain risk factors that help them decide about chemotherapy treatment and which drugs are best for you.

The scores for each risk factor are 0,1, 2 and 4. The risk factors are:

• age – the younger you are, the lower your score
• the type of pregnancy you had – a molar pregnancy is low risk, an abortion or miscarriage means a slightly higher risk, and full term pregnancy gives a higher score
• time between the pregnancy event and your diagnosis – less than 4 months is a low score and more than a year is a higher score
• the hCG level in the blood – the higher the level of hCG the greater the score
• the amount of tumour spread – the more areas of your body the tumour has spread to, the higher the score
• the parts of your body affected– tumour spread to the lungs or vagina is a low score, to the spleen or kidneys is a slightly higher score, and spread to the brain or liver is higher again
• the size of the tumour – the larger the tumour, the greater the score
• previous chemotherapy – if you have already had chemotherapy for your GTT but it has come back, this increases your score further

The doctors add up your scores to give a total and they group women into two groups – high risk or low risk.

Low risk means your risk factor score is 6 or less, and high risk means your score is 7 or more.

Most women needing treatment after a molar pregnancy will have a low risk score.