Hydatidiform Mole
TNM Definitions
AJCC Stage Groupings
Nonmetastatic GTTs
Good-Prognosis Metastatic GTTs
Poor-Prognosis Metastatic GTTs

Hydatidiform Mole

Hydatidiform mole (molar pregnancy) is disease limited to the uterine cavity.

Invasive mole (chorioadenoma destruens) is a locally invasive, rarely metastatic lesion.

The FIGO staging system is as follows:[1]

• Stage I: Disease confined to the uterus
  • Stage IA: Disease confined to the uterus with no risk factors.
  • Stage IB: Disease confined to the uterus with one risk factor.
  • Stage IC: Disease confined to the uterus with two risk factors.
• Stage II: Gestational trophoblastic tumor (GTT) extends outside of the uterus but is limited to the genital structures (ovary, tube, vagina, and broad ligament)
  • Stage IIA: GTT involving genital structures without risk factors.
  • Stage IIB: GTT extends outside of the uterus but is limited to genital structures with one risk factor.
  • Stage IIC: GTT extends outside of the uterus but is limited to the genital structures with two risk factors.
• Stage III: GTT extends to the lungs, with or without known genital tract involvement
  • Stage IIIA: GTT extends to the lungs, with or without genital tract involvement and with no risk factors.
  • Stage IIIB: GTT extends to the lungs, with or without genital tract involvement and with one risk factor.
  • Stage IIIC: GTT extends to the lungs, with or without genital tract involvement and with two risk factors.
• Stage IV: All other metastatic sites
  • Stage IVA: All other metastatic sites, without risk factors.
  • Stage IVB: All other metastatic sites, with one risk factor.
  • Stage IVC: All other metastatic sites, with two risk factors.

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification.[1]

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• T1: Disease limited to uterus
• T2: Disease outside of uterus but is limited to genital structures (ovary, tube, vagina, and broad ligaments)

Distant metastasis (M)

• M0: No clinical metastasis
• M1a: Lung metastasis
• M1b: All other distant metastasis

Risk factors affecting staging include the following:

1. Human chorionic gonadotropin (hCG) greater than 100,000 IU/24-hour urine.
2. The detection of disease more than 6 months from termination of the antecedent pregnancy.

Stage IA

• T1, M0, no risk factors

Stage IB

• T1, M0, one risk factor

Stage IC

• T1, M0, two risk factors

Stage IIA

• T2, M0, no risk factors

Stage IIB

• T2, M0, one risk factor

Stage IIC

• T2, M0, two risk factors

Stage IIIA

• Any T, M1a, no risk factors

Stage IIIB

• Any T, M1a, one risk factor

Stage IIIC

• Any T, M1a, two risk factors

Stage IVA

• Any T, M1b, no risk factors

Stage IVB

• Any T, M1b, one risk factor

Stage IVC

• Any T, M1b, two risk factors

Most major U.S. Trophoblastic Disease Centers have used a clinical classification system based on prognostic groups to determine treatment and report results. In the staging system below, GTT is divided into metastatic and nonmetastatic, with the former further divided into low-risk and high-risk based on:[2,3]

1. Duration of disease.
2. Presence or absence of liver or brain metastasis.
3. The hCG titer level.
4. Presence or absence of prior chemotherapy.
5. Occurrence after a full-term pregnancy.

Nonmetastatic GTT is defined as no disease outside the uterus. A diagnosis of nonmetastatic trophoblastic disease is made when there are persistently elevated hCG titers or a tissue diagnosis of uterine choriocarcinoma in the absence of detectable metastatic disease. One criterion used to make the diagnosis relates tumor load to the length of the hCG plateau.[4]

Indicated by the following factors:

1. Last pregnancy less than 4 months ago.
2. A low hCG titer (<100,000 IU [24-hour urine] or <40,000 mIU/mL blood).
3. No liver or brain metastases.
4. No prior chemotherapy.

Indicated by any of the following factors:

1. Last pregnancy more than 4 months ago.
2. A high hCG titer (>100,000 IU [24-hour urine] or >40,000 mIU/mL blood).
3. Liver or brain metastases.
4. Prior chemotherapy.
5. Occurrence after a full-term pregnancy.

Metastatic GTTs are also categorized by the WHO scoring system as low-risk, medium-risk, and high-risk.[5] This scoring system has been suggested for use in identifying the especially (“ultra”) high-risk patient who is best treated by the most dose-intensive and efficacious combination chemotherapy protocol. The WHO scoring system based on prognostic factors is listed below. The individual scores for each prognostic factor are added together to obtain a total score.[6] A total score less than or equal to four is considered low risk, a total score of five to seven is considered middle risk, and a total score of eight or greater is considered high risk. A study also examined the use of the WHO scoring system for reporting results of treatment; the results suggested that risk categories be redefined as low (<8), medium (8–12), and high (>12). Failure of treatment was limited to patients in the latter group.[7]

References

1. Gestational trophoblastic tumors. In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 5th ed. Philadelphia, Pa: Lippincott-Raven Publishers, 1997, pp 211-214. 
   
   
2. Lurain JR: Gestational trophoblastic tumors. Semin Surg Oncol 6 (6): 347-53, 1990.  [PUBMED Abstract]
   
   
3. Bagshawe KD: Risk and prognostic factors in trophoblastic neoplasia. Cancer 38 (3): 1373-85, 1976.  [PUBMED Abstract]
   
   
4. Kohorn EI: Evaluation of the criteria used to make the diagnosis of nonmetastatic gestational trophoblastic neoplasia. Gynecol Oncol 48 (2): 139-47, 1993.  [PUBMED Abstract]
   
   
5. World Health Organization Scientific Group.: Gestational trophoblastic diseases. Geneva: World Health Organization, 1983. 
   
   
6. Tumors of the placental trophoblast. In: Morrow CP, Curtin JP: Synopsis of Gynecologic Oncology. 5th ed. New York, NY: Churchill Livingstone, 1998, pp 315-353. 
   
   
7. Dubuc-Lissoir J, Sweizig S, Schlaerth JB, et al.: Metastatic gestational trophoblastic disease: a comparison of prognostic classification systems. Gynecol Oncol 45 (1): 40-5, 1992.  [PUBMED Abstract]