Stage and Risk Grouping for Gestational Trophoblastic Disease

Executive Summary for Gestational Trophoblastic Disease

The gestational trophoblastic disease stages help determine the tumor’s location and metastasis. The staging system for gestational trophoblastic disease uses diagnostic tests. There are four stages of gestational trophoblastic disease – stages I through IV (one through four). Women with a low-risk tumor score of 6 or less have a good prognosis, even if cancer has spread because the treatment is usually adequate. Women with a high-risk score of 7 or more require more intense treatment even if the tumor has not spread. The patient’s diagnosis is assigned to a stage group represented by a Roman numeral – I, II, III, and IV. Then, the sum of the prognostic factor scores is placed after a colon—for instance, stage II:4 or stage IV:9. Every patient with GTD will be assigned a location and score. For people with PSTT/ETT, only the stage will be given. A score of risk factors is not applicable in these cases.

Stage and Risk Grouping for Gestational Trophoblastic Disease

Staging is the procedure of determining where the tumor is located, whether it has spread or not, and how it grows. While assessing the cancer stage, many factors are taken into account.

Doctors use diagnostic tests to discover cancer’s stage, so staging may not be complete until all tests are finished. 

FIGO anatomic staging ​1​

  • Stage I – Disease is only in the uterus.
  • Stage II – GTD extends outside the uterus but is limited to the genital structures.
  • Stage III – GTD extends to the lungs and may not involve the genital tract.
  • Stage IV – GTD has extended to other distant sites.

World Health Organization Risk Score as used by FIGO

FIGO staging includes a risk score established by the WHO. This is because this prognostic risk score helps build an effective treatment plan for the patient.

The table described below shows how the risk score is determined. Each prognostic factor is assigned a score. Then, all those scores from each prognostic factor are added together to calculate the WHO risk score ​2​.

  • Low risk has a score of 6 or less. Women with a low-risk tumour have a good prognosis, even if cancer has spread because the treatment is usually effective.
  • High risk has a score of 7 or more. Women with a high-risk tumour may require more intense treatment even if the tumour has not spread.
Prognostic Factor0124
AgeYounger than 4040 or older
Previous pregnancyHydatidiform moleAbortionFull-term pregnancy
Months since last pregnancyLess than 44 to 67 to 12More than 12
Pretreatment hCG (IU/mL)Less than 103103 to 104Greater than 104 to 105105 or more
Largest tumor size, including uterusLess than 3 centimeters (cm)3 to less than 5 cm5 cm or more
Site of spreadLungSpleen or kidneyGastrointestinal tractBrain, liver
Number of tumors that have spread*Zero1 to 45 to 8More than 8
Number of drugs used to treat the tumor that have not workedNoneNone1 drug2 or more drugs

*For lung metastases, a chest x-ray (not the CT scan) is used to count the number of metastases.

The patient’s diagnosis is assigned to a stage group represented by a Roman numeral – I, II, III, and IV. Then, the sum of the prognostic factor scores is placed after a colon. For instance, stage II:4 or stage IV:9. Every patient with GTD will be assigned a stage and score.

For people with PSTT/ETT, only the stage will be assigned. A score of risk factors is not applicable in these cases.
Recurrent: Cancer that has come back after treatment is called recurrent cancer. If cancer returns, the doctor performs another round of tests to know the extent of the recurrence. These tests and scans are mainly similar to those done at the original diagnosis.

References

  1. 1.
    Gueye M. Diagnosis, Treatment and Outcomes of Gestational Trophoblastic Neoplasia in a Low Resource Income Country. Int J MCH AIDS. Published online 2016. doi:10.21106/ijma.108
  2. 2.
    Fariba B, Behtash N, Ghaemmaghami F, Moosavi A, Rezayof E, Gilani M. The WHO score predicts treatment outcome in low risk gestational trophoblastic neoplasia patients treated with weekly intramuscular methotrexate. J Can Res Ther. Published online 2013:38. doi:10.4103/0973-1482.110357