Oncologist-approved cancer information from the American Society of Clinical Oncology
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Gestational Trophoblastic Tumor

This section has been reviewed and approved by the Cancer.Net Editorial Board, 1/2012
Stages

Staging is a way of describing where the cancer is located, if or where it has spread, and whether it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer's stage, so staging may not be complete until all the tests are finished. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient's prognosis (chance of recovery). There are different stage descriptions for different types of cancer.

One tool that doctors use to describe the stage is the TNM system. This system judges three factors: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to the rest of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.

TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Typically in most types of cancer, doctors look at these three factors to determine the stage of cancer:

  • How large is the primary tumor and where is it located? (Tumor, T)
  • Has the tumor spread to the lymph nodes? (Node, N)
  • Has the cancer metastasized to other parts of the body? (Metastasis, M)

However, the traditional staging system does not adequately describe the staging of a GTT; therefore, to stage a GTT, the “N” or node category is removed and replaced with a risk factor score (see below). This score helps classify the tumor into either a low-risk and high-risk category.

Tumor. The "T" plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Some stages are also divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each individual. Specific tumor stage information is listed below:

TX: The primary tumor cannot be evaluated.

T0 (T plus zero): There is no tumor.

T1: The tumor is only in the uterus.

T2: The tumor has invaded other reproductive structures, such as the ovaries, vagina, or broad ligaments, by either metastasis or direct tumor growth.

Distant metastasis. The “M” indicates whether the cancer has spread to other parts of the body.

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): There is no distant metastasis.

M1: There is metastasis to other parts of the body.

M1a: There is metastasis to the lungs.

M1b: There is metastasis to any other area of the body.

World Health Organization (WHO) Risk Score

The table below shows how the risk score staging factor is determined. Low risk is a score of 7 or less, and high risk is a score of 8 or greater.

Risk Score

Prognostic Factor

0

1

2

4

Age

Younger than 40

40 and/or older

 

 

Previous pregnancy

Hydatidiform mole

Abortion

Full-term pregnancy

 

Months since last pregnancy

Less than 4

4 to 6

7 to 12

More than 12

Pretreatment hCG (IU/ml)

Less than 10³

Greater than or equal to 10³ to 104

104 to 105

Greater than or equal to 105

Largest tumor size, including uterus

Less than 3 cm

3 to 5 cm

Greater than or equal to 5 cm

 

Site of spread

Lung

Spleen, kidney

Gastrointestinal tract

Brain, liver

Number of tumors that have spread

 

1 to 4

5 to 8

More than 8

The number of drugs used to treat the cancer that have not worked

 

 

Single drug

Two or more drugs

Total Score

 

 

 

 

GTT Stage Grouping

For a GTT, doctors assign the stage by combining the T and M classifications and including a risk factor score.

Stage I: The tumor is only in the uterus and has not spread, and the patient has an unknown-risk score (T1, M0, Unknown risk).

Stage IA: The tumor is only in the uterus and has not spread, and the patient has a low-risk score (T1, M0, Low risk).

Stage IB: The tumor is only in the uterus and has not spread, and the patient has a high-risk score (T1, M0, High risk).

Stage II: The tumor has spread to other reproductive structures but has not spread elsewhere, and the patient has an unknown-risk score (T2, M0, Unknown risk).

Stage IIA: The tumor has invaded other reproductive structures but has not spread elsewhere, and the patient has a low-risk score (T2, M0, Low risk).

Stage IIB: The tumor has invaded other reproductive structures but has not spread elsewhere, and the patient has a high-risk score (T2, M0, High risk).

Stage III: The tumor is of any size and has spread to the lungs, and the patient has an unknown-risk score (Any T, M1a, Unknown risk).

Stage IIIA: The tumor is of any size and has spread to the lungs, and the patient has an low-risk score (Any T, M1a, Low risk).

Stage IIIB: The tumor is of any size and has spread to the lungs, and the patient has a high-risk score (Any T, M1a, High risk).

Stage IV: The tumor is of any size and has spread to other parts of the body beyond the lungs, and the patient has an unknown-risk score (Any T, M1a, Unknown risk).

Stage IVA: The tumor is of any size and has spread to other parts of the body beyond the lungs, and the patient has a low-risk score (Any T, M1a, Low risk).

Stage IVB: The tumor is of any size and has spread to other parts of the body beyond the lungs, and the patient has a high-risk score (Any T, M1a, High risk).

Recurrent: Recurrent cancer is cancer that comes back after treatment. If there is a recurrence, the cancer may need to be staged again (called re-staging) using the system above.

Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net.

FIGO Staging System

The Fédération Internationale de Gynécologie et d’Obstétrique (FIGO) uses the following staging system for GTT.

Stage I: The tumor is located only in the uterus.

Stage II: The tumor includes local metastases to the pelvis and vagina.

Stage III: The tumor involves pulmonary (lung) metastases.

Stage IV: The tumor consists of distant metastatic disease.

© 2005-2014 American Society of Clinical Oncology (ASCO). All rights reserved worldwide.

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