Gestational Trophoblastic Disease is a term used for a group of pregnancy-related tumors. The amount of information you receive at the time of diagnosis can feel overwhelming. We hope this information will help you understand your condition more thoroughly and help you through this difficult time.
Gestational Trophoblastic Disease (GTD) Overview
Gestational trophoblastic disease (GTD) is a rare group of interrelated tumors that develop following conception that lead to abnormal development of the placenta. More than 80% of GTD cases are non-cancerous. All forms of GTD can be treated, and in the great majority of cases the treatment results in a cure. Most women who have had a single incidence of GTD can go on to have normal pregnancies.
There are three main types of GTD:
1) Hydatidiform Mole
A hydatidiform mole (also called a “molar pregnancy”) is a form of GTD that arises when fertilization of an egg cell results in an abnormal pregnancy. There are two types of molar pregnancies, complete and partial. A complete molar pregnancy develops when the fertilized egg cell lacks maternal genes. The pregnancy that results contains no fetal tissue and resembles grape-like cysts that fill the uterine cavity. A partial molar pregnancy occurs when more than one sperm fertilizes a normal egg resulting in a pregnancy where both the fetus and placenta are abnormal. The term partial is used because the placenta contains both normal tissue and grape-like cysts similar to that seen in complete moles. 80% of molar pregnancies are benign in that they cause no further trouble after they are removed from the uterus. However, in approximately 20% of complete molar pregnancy and 1-4% of partial moles, the molar tissue either spreads locally within the muscular wall of the uterus (called invasive mole) or spreads more widely to other parts of the body, most commonly the lungs (called metastases), which requires treatment. Hydatidiform moles occur in only one of every 1000-1200 pregnancies in the United States.
Choriocarcinoma is a highly malignant form of GTD that spreads rapidly throughout the body and requires vigorous treatment. It may have begun as a molar pregnancy or from tissue that remains in the uterus following a miscarriage or childbirth. Choriocarcinoma is even less common, arising in only one of every 20,000-40,000 pregnancies.
3) Placental-Site Trophoblastic Tumor
Placental-site GTD is a very rare form of the disease that arises in the uterus at the site where the placenta was attached. These tumors penetrate the muscle layer of the uterus and usually do not spread to other parts of the body.
The Foundation for Women’s Cancer provides links to organizations that provide additional information on GTD. These can be found in the resources section.