Gestational Trophoblastic Disease (Molar Pregnancy)

The disease known as molar pregnancy among the people and is defined as gestational trophoblastic disease in medicine.  GTH is a disease related to many pathological developments, mainly due to hydatidiform mole (molar pregnancy), invasive mole, choriocarcinoma and placental site trophoblastic tumor, originating from the placental tissue. There are many types of GTH. The disease that occurs when GTH does not heal is called gestational trophoblastic tumor (GTT). GTT often occurs after a molar pregnancy (hydatidiform mole). It can rarely occur after miscarriage and normal pregnancy. Pathologically, GTT is frequently seen in two forms, invasive mole and choriocarcinoma.

Today, GTH is known as an easily curable disease that can be treated completely. There are several reasons for this. The first reason is that they secrete an important tumor marker such as hCG. The blood level of the substance called HCG rises above normal in all women with GTH and reaches very high levels. The second reason; the factors that determine the course of the disease are well known. The third and most important reason is that these tumors respond very well to chemotherapy.

GTH disease is a pregnancy related disease. Therefore, it is a common and important health problem in societies like our country where fertility rate is high. Although it varies from country to country, prevalence of this disease is 1 in every 1000 pregnancies.

Factors Related to GTH

  1. Race
  2. Characteristics of diet
  3. Age
  4. Number of Pregnancy
  5. Previous Hydatidorm Mole
  6. Birth Control Methods
  7. Smoking

Hydatidiform Mole

Hydatidiform mole (HM) is also called a molar pregnancy. It is the most common type of GTH and responds best to treatment. It has two types as incomplete (partial) and complete. In incomplete mole, there are intact parts of the fetus outside the diseased area inside the uterus. On the other hand, complete hydatidiform mole has no embryonic or fetal tissues and molar pregnancy fills the whole uterus. In most complete moles, all genes are inherited from the father only.

Clinical picture

75-80% of the mole cases apply to the clinic with abnormal vaginal bleeding. Abnormal vaginal bleeding occurs in most patients after a missed or delayed period. Therefore, the disease is often evaluated as a miscarriage at first. In gynecological examination, the uterus (womb) can be larger than the expected week of pregnancy. Thanks to ultrasound examinations, most of the mole cases can be recognized before the complaints emerge.

Pregnancy test is positive in mole cases. The levels the pregnancy hormone called HCG in urine and blood always elevated significantly. Ultrasound is very helpful in the early diagnosis of MH, as well as in the early diagnosis of GTT. 80% of complete MH cases and 30% of partial mole cases can be diagnosed by ultrasound before histopathological evaluation. From another point of view, ultrasound findings do not suggest diagnosis of mole in approximately half of the mole cases. For this reason, all abortion materials after emptying the fetal tissues inside the uterus should be sent to the pathology laboratory.

In addition to ultrasound, imaging methods such as CT scan and MRI can be used in diagnosis, but these methods should be used mostly in determining the spreading foci of GTTs.

Treatment of Hydatidiform Mole

The uterus should be emptied as soon as possible after the diagnosis of HM (hydatidiform mole – molar pregnancy) is made. Mole evacuation should be done with vacuum curettage and the entire interior area should be cleaned from molar pregnancy.

Follow-Up After Treatment

After mole evacuation, patients should be followed up at 7-10 day intervals until blood hCG level is normalized. The purpose of hCG follow-up is to identify ongoing GTD cases, in other words, gestational trophoblastic tumor (GTT) cases.

Apart from patients with GTT, the hCG blood level also rises in some ovarian tumors and in normal pregnancy. The disease is considered to be cured when the blood hCG level returns to normal in hCG measurements performed after evacuation of a molar pregnancy. However, patients should be followed up for one year with hCG measurements. The reason for this is that the disease can recur during this period. If the hCG level is within normal limits after one year, this means that HM is completely eliminated and the disease is considered to be completely cured. In this case, the follow-up is ceased.

After Human chorionic gonodatropin (hCG) returns normal levels after evacuation of the molar pregnancy, hCG measurement is performed once a month for the first 6 months, and once every 2 months for the next 6 months. During this period, the patient should not get pregnant. Birth control pills are recommended to prevent pregnancy.

In the hCG follow-ups performed after the evacuation of the molar pregnancy; if the hCG blood level remains the same or increases, the disease is called persistent (ongoing) trophoblastic disease or gestational trophoblastic tumor.

Gestational Trophoblastic Tumor

Although gestational trophoblastic tumor (GTT) frequently occurs after a molar pregnancy, it can also develop after abortion (miscarriage) and normal pregnancy. GTT can be seen in two ways; those that have not spread beyond the womb (non-metastatic) and those that have spread (metastatic).

Metastatic GTT occurs after 4% of HM cases. It can also occur following other pregnancies. Metastatic GTT can cause different complaints according to the areas of metastasis (spread). For example, patients who have a tumor spread to the lungs have coughs, spitting blood and shortness of breath, while those with spread to birth canal may have vaginal bleeding and those with metastasis in the brain may suffer from neurological complaints such as headache, vision disorders and dizziness. In GTT cases, tumor spread is seen in the lung (80%), vagina (birth canal) (30%), pelvis (groin) (20%), liver (10%) and brain (10%).

Diagnosis and Histological Types in GTT

As stated above, in hCG follow-ups performed after HM evacuation, if there is no change in blood hCG levels for 3 weeks or an increase occurs in blood hCG level for 2 consecutive weeks, it is considered abnormal. In this case, the disease is called persistent (ongoing) trophoblastic disease or gestational trophoblastic tumor. Patients whose hCG has not regressed within the normal limits for a period of more than six months and who have been diagnosed pathologically as choriocarcinoma also receives the diagnosis of GTT. The probability of developing persistent GTT after a molar pregnancy is 20% on average. Besides choriocarcinoma, GTT has different histopathological subtypes.

GTT (Malignant GTD)

  1. Invasive mole
  2. Choriocarcinoma
  3. Placental site tumor
  4. Epithelioid trophoblastic tumor
  5. Others

Invasive Mole

Invasive mole occurs when HM is seem within the wall of the uterus. It is a type of GTT that does not spread. It is a type of GTT likely to respond to treatment. With the widespread use of ultrasound examinations, the diagnosis of invasive moles is easy and can be made earlier.

Choriocarcinoma

It is a type of GTT that is very likely to spread. It spreads primarily via blood vessels. Because this feature, it can spread all over the body. The regions where it often spreads include the liver, birth canal and the brain. It can occur after molar pregnancy as well as after miscarriages or normal pregnancies.

As mentioned above, GTT has many subgroups besides choriocarcinoma. However, since these are very rare, they will not be mentioned here.

Clinical Evaluation

The first thing to be done before treatment in patients diagnosed with GTT is to investigate whether the disease has spread outside the uterus. There is no need to take a biopsy (sampling) most of the time during this research. With the ultrasound examination performed after gynecological examination, important information about the location and size of the disease in the uterus can be gained.

After these examinations, the lung and abdominal cavity tomography is performed as the second step, and if any, spreading areas are searched. For this purpose, MRI can be done.

After these studies, the stage (extent) of the disease is determined and treatment is given according to the stage.

GTT Treatment

In more than half (75%) of cases with GTT, the pathological tumor type is invasive mole. However, the choice of treatment in GTT is not related to the pathological type. In other words, tumor histology in GTT does not affect the treatment method.

As mentioned above, after diagnosis of GTT, prevalence or stage is determined by examination and imaging techniques, and treatment is started. Treatment of GTTs is done with chemotherapy. These tumors respond very well to chemotherapy drugs. However, in some special cases, radiotherapy and surgery may be required.

If the disease has not spread in the uterus and elsewhere, or if it has spread only to the lung, treatment is started with one of the chemotherapy drugs called methotrexate and actinomycin-D. If the disease has spread outside the lung and/or does not respond to single drug chemotherapy, treatment is carried out with multi-drug chemotherapy.

If the disease has not spread to the liver and brain before treatment, it will recover by 80-90%. The rate of recovery in tumors that have spread to these organs is about 60%.

Follow-Up After Treatment

More than 90% of GTT cases recover completely after treatment. The disease recurrence rates after treatment vary between 4% and 8%. Most of the recurrences were seen within 18 months from the moment the full response was received, in other words, when the hCG returned to normal. Recurrences are more common in high-risk GTT cases and choriocarcinomas.


Call Now
Directions