Stages of gestational trophoblastic disease (GTD)
Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the organ have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).
The most common staging system for gestational trophoblastic disease (GTD) is the FIGO system. For GTD, there are 4 stages. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.
The staging system for GTD does not apply to hydatidiform moles because they are usually non-cancerous. If a hydatidiform mole develops into cancer (an invasive mole), it will be staged then.
Find out more about staging cancer.
Stage 1
The tumour is only within the uterus.
Stage 2
The tumour has grown outside the uterus but only to reproductive organs, such as an ovary, a fallopian tube or the vagina, or to nearby areas, such as ligaments.
Stage 3
The tumour has spread to the lungs and may also have spread to the reproductive organs.
Stage 4
The cancer has spread to other parts of the body (called distant metastasis), such as to the brain or liver.
Recurrent or persistent GTD
Recurrent GTD means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it’s called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it’s called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.
Persistent GTD means that a hydatidiform mole has grown from the surface layer of the uterus into the muscle layer below or has spread to other organs.
Prognostic score
FIGO also uses the World Health Organization (WHO) prognostic scoring system based on several risk factors. It gives a score of 0, 1, 2 or 4 to each risk factor. This scoring system helps predict the outcome and determine the type of treatment given.
|
Risk factor |
Score |
|||
|---|---|---|---|---|
| 0 | 1 | 2 | 4 | |
| Age | younger than 40 | 40 or older | ||
| Type of pregnancy | hydatidiform mole | spontaneous or elective abortion | full-term pregnancy | |
| Number of months since last pregnancy | less than 4 | 4 to 6 | 7 to 12 | more than 12 |
| HCG level (IU/mL) before treatment | less than 1,000 | 1,000 to 9,999 | 10,000 to 100,000 | greater than 100,000 |
| Size of largest tumour, including the original tumour in the uterus | less than 3 cm across | at least 3 cm but less than 5 cm | 5 cm or more | |
| Site of disease spread (metastases) | lung | spleen, kidney | gastrointestinal tract (stomach, intestines) | brain, liver |
| Number of metastases | 0 | 1 to 4 | 5 to 8 | more than 8 |
| Previous unsuccessful chemotherapy | none | none | single drug | 2 or more drugs |
All scores are added together to give an overall prognostic score. This is used to group GTD as low risk or high risk.
Low-risk GTD has a prognostic score of 1 to 6.
High-risk GTD has a prognostic score of 7 or more.
The prognostic group is usually reported as the FIGO stage followed by a colon and the sum of all the actual risk scores.
Another way to report the prognostic group is by using the letter A for low risk and the letter B for high risk without giving the actual risk score. For example, stage 2A refers to low-risk stage 2.
For women with placental site trophoblastic tumour and epithelioid trophoblastic tumour, only a FIGO stage is given.