A rise in the hormone level indicates that the molar pregnancy has become malignant and will be called gestational trophoblastic neoplasia (GTN). More tests will be done to find out if the cancer has spread from the uterus to other parts of the body (called staging). Even if GTN has spread to other parts of the body, it is still highly curable. The stages of malignant GTN are:
- Stage I: The cancer has not spread from the uterus
- Stage II: The cancer has spread from the uterus to other structures in the pelvis
- Stage III: The cancer has spread to the lungs
- Stage IV: The cancer has spread to other organs
In addition to stage, GTN is also assigned a risk score, calculated by a number of clinical characteristics, which will determine the type of chemotherapy that will most likely cure the disease. The factors that are characteristic of women who are likely to be cured by one or more single chemotherapy drugs (called low-risk GTN) include:
- The last pregnancy was less than four months ago
- The level of hCG in the blood is low
- The cancer has not spread to the liver, brain, and/or other distant organs
- The patient has not received chemotherapy treatments earlier
The risk factors for women who develop GTN who are NOT likely to be cured by one or more single chemotherapy drugs and who require treatments containing multiple agents (called high-risk malignant GTN) are:
- The last pregnancy was more than four months ago
- The level of hCG in the blood is very elevated
- The cancer has spread to the liver, brain, and/or other distant organs
- The patient received chemotherapy earlier and the cancer did not go away
- The tumor began after completion of a normal pregnancy
Chemotherapy for GTN continues until hCG normalizes. Once this is achieved, three additional cycles of consolidation chemotherapy are given.
After completion of chemotherapy, testing for human chorionic gonadotropin (hCG) in the patient’s blood continues monthly for 12 months (24 months for patients with Stage IV disease). During that time, patients should avoid pregnancy. If pregnancy occurs before follow-up is complete, tumor relapse may be difficult to detect, and diagnosis of relapse may be delayed.
The chemotherapy used for the treatment of GTN is generally well tolerated without long-term side effects, with two exceptions — the use of multi-agent chemotherapy is associated with an earlier menopause and a low risk of secondary tumors.
GTD is a highly curable disease. Women with hydatidiform mole have an excellent prognosis and rarely need treatment, while women with GTN also have a very good prognosis but require treatment. Choriocarcinoma, for example, is an uncommon — yet almost always curable — cancer. Although choriocarcinoma is a highly malignant tumor and life-threatening disease, it is very sensitive to chemotherapy. About 85 to 90 percent of women with low-risk GTN are cured by the initial chemotherapy, and the remaining are cured by stronger combinations of drugs, or by surgery.
Similarly, 85-90 percent of women who develop high-risk GTN are cured by chemotherapy used together with selective surgery and radiation.
Approximately 10-15 percent of women with high-risk GTN will develop drug resistance after prolonged chemotherapy. This group often consists of patients with stage IV disease that involves distant organs such as the brain, liver, and bowel. Specially-designed
chemotherapy treatments using drugs that have been shown to be effective against other cancers are being employed to assist in treating many of these women.
Three kinds of treatment can be used for GTN:
- Chemotherapy (using drugs to eliminate the cancer)
- Radiation therapy (uses high energy x-rays to eliminate cancer cells and shrink tumors)
- Surgery (removing the cancer)
Chemotherapy is the main treatment for GTN and is generally highly effective. Chemotherapy uses drugs to eliminate cancer cells. It may be taken by pill, or by a needle in vein or muscle. It is called systemic treatment because the drugs
enter the bloodstream, travel through the body, and can kill cancer cells both inside and outside the uterus. Chemotherapy may be given before or after surgery or alone. Patients can preserve fertility and still be cured with chemotherapy even in the presence of
Radiation may infrequently be used in certain cases to treat cancer that has spread to other parts of the body, particularly the brain. Radiation may come from a machine outside the body (external-beam radiation therapy) or from materials that produce radiation (radioisotopes) inserted through thin plastic tubes into the area where the cancer cells are found (internal radiation).
Surgery is used for a variety of reasons in the management of GTN. The most common surgery for GTN is hysterectomy, an operation to remove the uterus. Surgery may also be used to remove cancer involving the lungs and other organs that has not gone away with drug therapy.
Placental-site and epithelioid trophoblastic tumors are less sensitive than choriocarcinoma to chemotherapy. Since in most cases the tumor is localized to the uterus, hysterectomy provides the best outcome. When the disease spreads outside the uterus, high-dose chemotherapy is used with some success.
Becoming pregnant again
After completing hormone follow-up for hydatidiform mole, women may try to become pregnant whenever they wish. The risk of another molar pregnancy is low. More than 98 percent of women who become pregnant following a molar pregnancy will have a normal pregnancy and are not at increased risk for pregnancy related complications. However, since patients with hydatidiform mole are at some increased risk of another molar pregnancy, it is advisable for them to undergo ultrasound examinations at 10 weeks of gestation to determine if the pregnancy is progressing normally. We also recommend that they have their hCG checked six to eight weeks after delivery to ensure that it has returned to normal.
Most women who require treatment for GTN can become pregnant again and have normal pregnancies. After chemotherapy is completed, women should postpone pregnancy for 12 months (24 months for women with stage IV disease) while they are being followed with hormone testing to make sure the tumor does not recur. There does not appear to be an increased rate of congenital malformation irrespective of the chemotherapy used. Following GTN, the expectation of normal pregnancies is comparable to the general population.