Gestational trophoblastic disease is a tumor originating from the trophoblast, which surrounds the blastocyst and develops into the chorion and amnion (see page Placenta and embryo at about 11 4/7 weeks gestation).
Gestational trophoblastic disease can occur during or after an intrauterine or ectopic pregnancy. If the disease occurs during a pregnancy, spontaneous abortion, eclampsia, or fetal death typically occurs; the fetus rarely survives.
Gestational trophoblastic disease may be
Hydatidiform moles are most common among women < 17 or > 35 and those who have previously had gestational trophoblastic disease. They occur in about 1/2000 gestations in the US. For unknown reasons, incidence in Asian countries approaches 1/200.
Most (> 80%) hydatidiform moles are benign. The rest may persist, tending to become invasive; 2 to 3% of hydatidiform moles are followed by choriocarcinoma.
Half of gestational trophoblastic neoplasms develop from a molar pregnancy, 25% from miscarriages or tubal pregnancy, and 25% from a term or preterm pregnancy (3). After a molar pregnancy, trophoblastic neoplasms usually develop as molar tissue or choriocarcinoma or, rarely, a placental site trophoblastic tumor or epithelioid trophoblastic tumor.
There are two types of molar pregnancy:
After a complete hydatidiform mole, local invasion occurs in 15% of cases, and metastatic disease occurs in 5%. After a partial mole, local invasion occurs in up to 3 to 5% and metastatic disease is rare (3).
General references
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1. Smith HO: Gestational trophoblastic disease epidemiology and trends. Clin Obstet Gynecol (3):541–556, 2003. doi: 10.1097/00003081-200309000-00006.
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2. Ngan S, Seckl MJ: Gestational trophoblastic neoplasia management: an update. Curr Opin Oncol 19 (5):486–491, 2007. doi: 10.1097/CCO.0b013e3282dc94e5.
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3. Goldstein DP, Berkowitz RS: Current management of gestational trophoblastic neoplasia. Hematol Oncol Clin North Am 26 (1):111–131, 2012. doi: 10.1016/j.hoc.2011.10.007.
Symptoms and Signs
Initial manifestations of a hydatidiform mole suggest early pregnancy, but the uterus often becomes larger than expected within 10 to 16 weeks gestation. Commonly, women test positive for pregnancy and have vaginal bleeding and severe vomiting, and fetal movement and fetal heart sounds are absent. Passage of grapelike tissue strongly suggests the diagnosis.
Complications, such as the following, may occur during early pregnancy:
Placental site trophoblastic tumors tend to cause bleeding.
Choriocarcinoma usually manifests with symptoms due to metastases.
Hyperthyroidism is more common among women with gestational trophoblastic disease than in those without. Symptoms can include a tachycardia, warm skin, sweating, heat intolerance, and mild tremors.
Gestational trophoblastic disease does not impair fertility or predispose to prenatal or perinatal complications (eg, congenital malformations, spontaneous abortions) in subsequent pregnancies.
Diagnosis
Gestational trophoblastic disease is suspected in women with a positive pregnancy test and any of the following:
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Uterine size much larger than expected for dates
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Symptoms or signs of preeclampsia
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Passage of grapelike tissue
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Suggestive findings (eg, mass containing multiple cysts, absence of a fetus and amniotic fluid) seen during ultrasonography done to evaluate pregnancy
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Unexplained metastases in women of child-bearing age
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Unexpectedly high levels of beta-hCG detected during pregnancy testing (except for placental site trophoblastic tumor and epithelioid trophoblastic tumor, which result in low beta-hCG levels)
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Unexplained complications of pregnancy
If gestational trophoblastic disease is suspected, testing includes measurement of serum beta-hCG and, if not previously done, pelvic ultrasonography. Findings (eg, very high beta-hCG levels, classic ultrasonographic findings) may suggest the diagnosis, but biopsy is required. Typically, beta-hCG levels are high in patients with invasive mole or choriocarcinoma and low in those with placental site trophoblastic tumor or epithelioid trophoblastic tumor.
Invasive mole and choriocarcinoma are suspected if biopsy findings suggest invasive disease or if beta-hCG levels remain higher than expected after treatment for hydatidiform mole (see below).
Thyroid function tests are done if the beta-hCG level is > 100,000 mIU/mL (> 100,000 IU/L) to check for hyperthyroidism.
Staging
A stage and risk score are assigned before gestational trophoblastic disease is treated.
The International Federation of Gynecology and Obstetrics (FIGO) has developed a staging system for gestational trophoblastic neoplasia (see table FIGO Anatomic Staging of Gestational Trophoblastic Neoplasia).
FIGO Anatomic Staging of Gestational Trophoblastic Neoplasia
Prognosis
In metastatic disease, the World Health Organization (WHO) prognostic scoring system for metastatic gestational trophoblastic disease can help predict prognosis, including risk of death (see table WHO Scoring System in Metastatic Gestational Trophoblastic Disease).
WHO Scoring System in Metastatic Gestational Trophoblastic Disease*
Poor prognosis is also suggested by the following (National Institutes of Health [NIH] criteria):
Treatment
(See also National Comprehensive Cancer Network (NCCN): NCCN Clinical Practice Guidelines in Oncology: Gestational Trophoblastic Neoplasia.)
Hydatidiform mole, invasive mole, placental site trophoblastic tumor, and epithelioid trophoblastic tumor are evacuated by suction curettage. Alternatively, if childbearing is not planned, hysterectomy may be done.
After tumor removal, gestational trophoblastic disease is classified clinically to determine whether additional treatment is needed. The clinical classification system does not correspond to the morphologic classification system. Invasive mole and choriocarcinoma are classified clinically as persistent disease. The clinical classification is used because invasive mole and choriocarcinoma are treated similarly and because exact histologic diagnosis may require hysterectomy.
A chest x-ray is taken, and serum beta-hCG is measured. If the beta-hCG level does not normalize within 10 weeks, the disease is classified as persistent. Persistent disease requires CT of the brain, chest, abdomen, and pelvis. Results dictate whether disease is classified as nonmetastatic or metastatic.
Persistent disease is usually treated with chemotherapy. Treatment is considered successful if at least 3 consecutive serum beta-hCG measurements at 1-week intervals are normal. Pregnancy should be prevented for 6 months after treatment because pregnancy would increase beta-hCG levels, making it difficult to determine whether treatment has been successful. Typically, oral contraceptives (any is acceptable) are given for 6 months; alternatively, any effective contraceptive method can be used.
Nonmetastatic disease can be treated with a single chemotherapy drug (methotrexate or dactinomycin). Alternatively, hysterectomy is considered for patients > 40 or those desiring sterilization and may be required for those with severe infection or uncontrolled bleeding. If single-drug chemotherapy is ineffective, hysterectomy or multidrug chemotherapy is indicated. Virtually 100% of patients with nonmetastatic disease can be cured.
Low-risk metastatic disease is treated with single-drug (eg, methotrexate, dactinomycin) chemotherapy preferably or with multidrug chemotherapy. High-risk metastatic disease requires aggressive multidrug chemotherapy because patients are likely to develop resistance if a single drug is used. EMA-CO is the most widely used regimen. It consists of etoposide, methotrexate, plus dactinomycin (EMA), alternating with cyclophosphamide plus vincristine (CO).
Cure rates are
Risk of disease progression and resistance to single-drug chemotherapy is determined by the FIGO staging system and the WHO risk scoring system.
Gestational trophoblastic disease is considered low risk if it is one of the following:
Gestational trophoblastic disease is considered high risk if it is one of the following:
Hydatidiform mole recurs in about 1% of subsequent pregnancies. Patients who have had a mole require ultrasonography early in subsequent pregnancies, and the placenta should be sent for pathologic evaluation.
Key Points
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Suspect gestational trophoblastic disease if uterine size is much larger than expected for dates, if women have symptoms or signs of preeclampsia, if beta-hCG levels are unexpectedly high during early pregnancy, or if ultrasonographic findings suggest gestational trophoblastic disease.
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Measure beta-hCG level, do pelvic ultrasonography, and if findings suggest gestational trophoblastic disease, confirm the diagnosis by biopsy.
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Remove the tumor (eg, by suction curettage), then classify the tumor based on clinical criteria.
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If disease is persistent, treat patients with chemotherapy and prescribe posttreatment contraception for 6 months.
More Information
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
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National Cancer Institute: Gestational Trophoblastic Disease Treatment: This web site provides information about gestational trophoblastic disease, its classification, staging, and treatment of each type of gestational trophoblastic disease.
