Gestational Trophoblastic Disease Definition
The condition refers to a group of tumors that develop inside the uterus in many pregnant women. As the name suggests, the abnormal growths occur in the trophoblast, the outermost layer of the blastocyst that serves as a nutritive pathway for the embryo. It is simply abbreviated as GTD and known by other names like:
- Gestational trophoblastic tumor
- Persistent gestational trophoblastic disease
Gestational Trophoblastic Disease Types
The condition is usually marked by any one of the following types of tumor that originate from the trophoblastic cells and grow in the placenta:
This is a benign tumor that appears as a mass of cysts resembling a bunch of grapes. It is further divided into:
- Complete hydatidiform mole
- Partial hydatidiform mole
The cancerous lesion occurs when a partial or complete hydatidiform mole invades the walls of the uterus and begins to spread to other parts of the body.
It is a highly malignant tumor that tends to metastasize early as well as widely through both the venous and lymphatic systems.
Placental site trophoblastic tumor
The cancerous lump predominantly consists of intermediate trophoblastic cells with fibrinoid material and vascular invasion.
Epithelioid trophoblastic tumor
This is a rare post-gestational tumor that comprises of epithelioid cells.
Gestational Trophoblastic Disease Staging
According to the International Federation of Gynecology and Obstetrics (FIGO), GTD develops through the following stages:
The disease is localized in the uterus.
GTD begins to spread outside the uterus but does not go beyond the genital structures like adnexa, vagina and broad ligament.
At this stage, cancer reaches the lungs even in the absence of a genital tract involvement.
Development of malignant growths on the potential metastatic sites marks the final stage of GTD.
Gestational Trophoblastic Disease Symptoms
The anomalous mass may appear during or after pregnancy. Some common indicators of GTD are given below:
- Irregular vaginal bleeding or discharge
- Abdominal swelling
- Enlarged uterus
- Severe pelvic pain
- Frequent vomiting
- Decreased fetal movement
- Shortness of breath
Gestational Trophoblastic Disease Causes
GTD can falsely represent pregnancy, owing to the presence of abnormal fetal tissue inside the uterus. Interestingly, the tissue grows at a normal rate and produces chorionic gonadotropin, a hormone produced by the placenta that maintains the corpus luteum during pregnancy. Although a fertilized egg implants into the uterus, some surrounding fetal cells fail to develop properly. Ultimately, the growing mass of cells takes the form of a benign tumor. Medical investigators attribute hydatidiform moles to excessive growth of the placenta. The fetus fails to receive proper nourishment and undergoes a delayed development. Complete hydatidiform moles are, however, devoid of fetal tissue and maternal DNA. On the other hand, partial hydatidiform moles are present with fetal cells due to dispermic fertilization of a normal ovum. Some of the other causes of GTD may include:
- Ectopic pregnancy
- Genital tumor
Gestational Trophoblastic Disease Risk Factors
GTD most often affects women under the age of 20 or who are above 35 years. Young females below the age of 16 have a six times higher risk of developing hydatidiform mole than those between the ages of 16 and 40. Most sufferers of GTD belong to the Asian population. Choriocarcinoma is more common in women with blood group A.
Gestational Trophoblastic Disease Diagnosis
Immediate diagnosis is warranted in case a patient suffers from vaginal bleeding and intense pelvic pain.
Elevated levels of chorionic gonadotropin hormone could either indicate GTD or pregnancy.
The grape-like benign tumor in the second trimester appears like a snowstorm during an ultrasound of the uterus. However, the technique cannot precisely detect a hydatidiform mole.
X-ray of the chest can inspect stage 3 of the disease.
MRI or CT scan of the brain and liver may help in assessing the impact of the malignant tumor on these vital organs.
Gestational Trophoblastic Disease Treatment
Most health specialists prefer suction curettage as a reliable tool for evacuation of pregnancy. In this procedure, the cervix, the opening of the uterus, is dilated by inserting a small rod or sponge. After dilation, a plastic tube is made to enter the uterus through the enlarged cervix. The tube is normally attached to a suction pump that sucks the fetus, placenta, and other uterine contents. The walls of the uterus are gently scraped to remove the fragments of the fetus and placenta with the help of a sharp, spoon-like instrument called curette. In case a patient does not want to achieve pregnancy in the future, hysterectomy is a valid curative option. This technique involves partial or complete removal of the uterus. Hydatidiform moles may receive intravenous methotrexate for a quick recovery. Dactinomycin is a potent chemotherapy drug for malignant conditions. Specific organs are subjected to radiation therapy to control the spread of the disease.
Gestational Trophoblastic Disease Prognosis
Patients with non-malignant tumors recuperate well. The prognosis is satisfactory in the case of malignant GTD. The fertility is not affected as long as the condition does not metastasize. However, sufferers who receive multi-agent chemotherapy are likely to have an earlier menopause and may develop secondary cancers.
Unlike other forms of cancer, Gestational Trophoblastic Disease stops metastasizing after a while. Regular follow up post treatment prevents the risk of developing malignant uterine invasion or malignant metastatic disorder. Patients treated with chemotherapy drugs should not conceive for one year until their chorionic gonadotropin levels normalize. During this period, barrier methods of contraception must be used instead of combined oral contraceptive pills to reduce the risk of uterine perforation. The possibility of recurrence is low and more than 98% of women who become pregnant do not undergo any obstetric complications.