Gestational Trophoblastic Disease
Gestational trophoblastic disease (GTD) is the name given to a group of rare tumors that develop during early pregnancy. After conception, tissue grows to form part of the placenta and surrounds the fertilized egg in the uterus, forming what’s called a trophoblast. In GTD, abnormal changes in the trophoblast cells cause tumors to develop. Most GTD tumors are benign, or noncancerous. However, some could become malignant and spread to nearby tissues or distant parts of the body.
There are a number of different variants of GTD. The most common types are:
This is the most common type of GTD, which occurs after a woman experiences a miscarriage. This is otherwise known as molar pregnancy, and happens in about 1 out of 1000 pregnancies in the US. These moles are slow growing tumors that look like sacs of fluid, or clusters of grapes on a sonogram. Hydatiform moles can be complete or partial moles depending upon the makeup of the sperm and egg’s DNA during conception.
Gestational Trophoblastic Neoplasia (GTN)
This is an abnormality that behaves like cancer. About half of GTN comes from molar pregnancy. About 25% comes from miscarriages or ectopic pregnancy, and about 25% follows term or preterm pregnancy. The following are different types of GTN:
- Invasive moles, which develop from hydatidiform moles
- Placental-site trophoblastic tumors (PSTT)
- Epithelioid trophoblastic tumors (ETT)
Most molar pregnancies are benign, but some can become malignant. The following are some risk factors that increase the chance of developing GTD, including signs during pregnancy that you should discuss with your doctor:
- Pregnancy before age 20 or after age 35
- Asian, American Indian, and African ancestry
- History of prior molar pregnancies
- History of infertility or prior miscarriages
Some of the symptoms caused by GTD can include:
- Vaginal bleeding during pregnancy or not related to menstruation
- Uterine size larger than expected during pregnancy
- Severe nausea and vomiting during pregnancy
- High blood pressure, with headache and swelling early during pregnancy
- Shortness of breath, dizziness, and fast and irregular heartbeat caused by anemia during pregnancy
- Signs of thyroid irregularities: feeling tired, short of breath, fast heartbeat, shakiness, sweating, trouble sleeping, weight loss, more frequent bowel movements
If you experience any of these symptoms, you should speak to your doctor.
To diagnose GTD, your doctor will need to perform a complete physical exam, including a pelvic exam that looks at and feels for abnormalities of the vagina, cervix, uterus, fallopian tubes, ovaries, and rectum. In addition, the following procedures may be performed:
- Ultrasound exam of the pelvis
- Blood tests, including checking for levels of b-hCG, a pregnancy hormone that is significantly elevated in women with GTD or a molar pregnancy
- Urine studies
- Curetting of inside of uterus to obtain tissue samples
Hydatidiform moles, or molar pregnancy, are found in the uterus only and do not spread. These conditions are not considered cancerous.
Gestational trophoblastic neoplasia (GTN) is considered cancerous and can spread to other parts of the body.
When GTN spreads to another part of the body, it is called metastasis. The process to find out if cancer has spread is called cancer staging. After diagnosis, tests are done to find out if cancer has metastasized:
- Chest X-ray to see if the cancer has spread to your lungs
- A CT (computed tomography) scan of your abdomen and pelvis, which converts data from different angles of X-ray images of your body into pictures on a monitor
- An MRI (magnetic resonance imaging) test, which uses powerful magnetic fields to create a 3D picture of your lower abdomen and pelvis to detect tumors
- Lumbar Puncture: a procedure to collect spinal fluid from the spinal canal
A description of the different stages of GTN is as follows:
- Stage I. Cancer is found limited within the uterus.
- Stage II. The cancer has spread outside of the uterus to the ovary, fallopian tube, and vagina.
- Stage III. The cancer has spread to the lung.
- Stage IV. The tumor has spread to other areas beyond other than lungs.