How Is Gestational Trophoblastic Disease Staged?

Staging is the process of finding out how far a cancer has spread. Doctors use this information to choose the type of treatment that offers the best possible results.

Molar pregnancies (complete and partial moles) are usually completely removed during a D&C (or, rarely, a hysterectomy), so they don't need to be surgically "staged." Staging is more useful for persistent Gestational trophoblastic (jeh-STAY-shuh-nul troh-fuh-BLAS-tik) disease, including invasive moles and choriocarcinomas (KOR-ee-oh-KAR-sih-NOH-muhs).

Gestational trophoblastic disease (GTD) classification

Most cancers are staged based on how large they are and whether they have spread to lymph nodes or distant sites. Then treatment is decided based on the stage. Stage is also used to predict a patient’s outlook. But because treatment for GTD is usually effective regardless of the extent of the disease, other factors such as a woman's age, length of time since pregnancy, and HCG level are more useful in predicting a woman's outlook (prognosis). These factors are taken into account in a scoring system.

Prognostic scoring system

In the United States, most cancer centers use a system that describes women with persistent GTDs according to their outlook, based on several factors.

Age

Score

Younger than 40

0

40 or older

1

   

Preceding pregnancy

Score

Molar pregnancy

0

Abortion (includes miscarriage)

1

Birth (term pregnancy)

2

   

Time since pregnancy

Score

Less than 4 months

0

At least 4 months but less than 7 months

1

7 to 12 months

2

More than 12 months

4

   

Blood HCG level (IU/L) before treatment

Score

Less than 1,000

0

1,000 − 9,999

1

10,000 − 99,999

2

100,000 or more

4

   

Largest tumor size,

including the original one in the uterus

Score

Less than 3 cm (1.2 inches) across

0

At least 3 cm but less than 5 cm (2 inches)

1

5 cm or more

2

   

Site of metastases (if any)

Score

Lung

0

Spleen, kidney

1

Gastrointestinal tract

2

Brain, liver

4

   

Number of metastases found

Score

0

0

1 to 4

1

5 to 8

2

More than 8

4

   

Prior failed chemotherapy

Score

None

0

Single drug

2

2 or more drugs

4

The numbers are then added up, and the overall score determines a woman's risk level.

  • Women with a score of 6 or less are at low risk and tend to have a good outlook regardless of how far the cancer has spread. The tumor(s) will usually respond well to chemotherapy.
  • Women with a score of 7 or more are at high risk, and their tumors tend to respond less well to chemotherapy, even if they haven't spread much. They may require more intensive chemotherapy.

FIGO anatomic staging

The International Federation of Gynecology and Obstetrics (FIGO) developed a staging system based on the extent of the GTD as follows:

Stage I: The tumor is still within the uterus.

Stage II: The tumor has grown outside the uterus into other genital structures (like the vagina or ovaries). It has not spread outside the pelvis.

Stage III: The tumor has spread to the lungs; and it may also involve genital structures such as the vagina or vulva.

Stage IV: The tumor has spread to distant organs such as the brain, liver, kidneys, and/or gastrointestinal tract.

Stage grouping

Stage grouping is a process that some doctors use that combines the prognostic score and the anatomic stage. This is listed as the anatomic stage, followed by the letter A if the prognostic score was low risk or B if the prognostic score resulted in high risk.

Stage IA: The tumor has not spread outside the uterus, and the prognostic score puts you at low risk.

Stage IB: The tumor has not spread outside the uterus, and the prognostic score puts you at high risk.

Stage IIA: The tumor has grown outside of the uterus but not beyond the vagina or pelvis, and the prognostic score puts you at low risk.

Stage IIB: The tumor has grown outside of the uterus but not beyond the vagina or pelvis, and the prognostic score puts you at high risk.

Stage IIIA: The tumor has spread to the lungs, and may or may not also involve genital structures such as the vagina or vulva. The prognostic score puts you at low risk.

Stage IIIB: The tumor has spread to the lungs, and may or may not also involve genital structures such as the vagina or vulva. The prognostic score puts you at high risk.

Stage IVA: The cancer has spread to distant organs such as the brain, liver, kidneys, and/or gastrointestinal tract. The prognostic score puts you at low risk.

Stage IVB: The cancer has spread to distant organs such as the brain, liver, kidneys, and/or gastrointestinal tract. The prognostic score puts you at high risk.

Another option combines the anatomic stage with the actual prognostic score number (separated by a colon). An example of this is II:5.

If GTD comes back after treatment (recurs), the disease is "restaged." This takes into account where the disease is in the body, along with the prior treatment.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: November 21, 2017 Last Revised: November 28, 2017

American Cancer Society medical information is copyrighted material. For reprint requests, please see our Content Usage Policy.