Gestational Trophoblastic Disease (GTD)

Tumors can grow anywhere in the body and then occur when the cells in the body begin to come out of control. Some tumors may have cancerous cells within them, and some may not. Cells can be cancerous in almost any part of the body, and can spread to other areas of the body. To know more about how cancers begin and spread, what is cancer?

Gestational trophoblastic disease (GTD) is a group of rare tumors that involves abnormal growth of cells inside a woman’s uterus. GTD cervical cancer or endometrial (uterine lining) does not develop from the uterus cells of cancer. Instead, they start in tumor cells, which usually develop in placenta during pregnancy. (The term gestational refers to pregnancy.)

GTD starts in the layer of cells called trophoblast, which is usually surrounded by embryos. (Tropho-nutrition means, and -blast means bud or initial growth cell.) In early development, cells of trophoblast are known as tiny, finger-like projections known as villi. villi grows in the uterus layer. In time, the trophoblast layer develops in placenta, the organ that protects and nourishes the growing embryo.

You call GTDs asgestational trophoblastic disease, gestational trophoblastic tumors, or gestational trophoblastic neoplasia. (neoplasia simply means new development. Most GTDs are benign (not cancer) and they do not attack deeply in body tissues or spread to other parts of the body. But there are some deadly (cancerous) cases.

All forms of GTD can be treated. And in most cases the treatment produces a complete treatment.

Types of gestational trophoblastic disease

The main types of gestational trophoblastic diseases are:
•  Hydatidiform mole (complete or partial)
•  Invasive mole
•  Choriocarcinoma
•  Placental-site trophoblastic tumor
•  Epithelioid trophoblastic tumor

Hydatidiform mole

The most common form of gestational trophoblastic disease (GTD) is a hydatidiform mole, also called molar pregnancy. It is made of villi which has become swollen with fluid. Swelling grow in the villi cluster, which look like a grape bunch. This is called a molar pregnancy, but this is not possible for the normal child. Even in rare cases (less than 1 in 100), a common embryo can develop with lent of molar pregnancy. Hydatidiform moles are not cancerous, but they can grow in cancer GTD.

There are 2 types of Hydatidiform moles: Complete and Partial.

A Complete Hydatidiform mole often develops when 1 or 2 sperm cells fertilize an egg cell, in which there is no nucleus or DNA (a “empty” egg cell). All genetic material comes from the father’s sperm cell. Therefore, there is no embryonic tissue.

Surgery can completely remove completely completely, but 1 in 5 women will have some consistent beard tissue (see below). Often it is an aggressive mole, but in rare cases it is a deadly (cancerous) form of choriocarcinoma, GTD. In any case, it will require further treatment.

A Partial Hydatidiform mole develops when 2 sperms lay normal eggs. These tumors contain some embryonic tissues, but it is often mixed with trophoblastic tissue. It is important to know that a viable (capable living) embryo is not being made.

Partial mole is usually removed completely from surgery. After partial surgery only a few young women need further treatment after initial surgery. Partial moles rarely develop in fatal GTD.

Persistent gestational trophoblastic disease GTD that is not cured by initial surgery. Continuous GTD occurs when the hydatidiform mole is grown in the muscle layer below the uterine surface layer (myometrium). Surgery used for the treatment of a hydatidiform mole (called suction dilation and curettage, or D&C), scraps inside the uterus. It removes only the internal layer of uterus (endometrium) and can not remove the tumor grown in the muscle layer.

Most cases of persistent GTD are invasive malls, but in rare cases they are choriocarcinomas or placental sites trophoblastic tumors (see below).

Invasive mole

An invasive mole (previously known as chorioadenoma destruens) is a hydatidiform mole that is grown in the uterine muscle layer. Invasive moles can either be developed from complete or partial moles, but complete moles become invasive much more often than do partial moles. Invasive moles develop in less than 1 in 5 women, with a complete mole removed. The risk of developing an invasive mole in these women increases if:

•  There is a long time (more than 4 months) between their previous menstrual period and treatment.
•  The uterus has become very big.
•  The woman is over 40 years old.
•  In the past, there was a gestational trophoblastic disease to the woman.

Since these moles are grown in the uterine muscle layer, they are not completely removed during D & C. Invasive moles can sometimes go away from themselves, but often require more treatment.

A tumor or mole that grows fully through the uterine wall, resulting in bleeding in the abdomen or pelvic cavity. This bleed can put life in danger.

Occasionally after removing a complete hydatidiform mole, the tumor spreads to other parts of the body (metastasizes), often in the lungs. It is about 4% of the time (or 1 out of 25 cases).

Choriocarcinoma

Choriocarcinoma is a deadly form of gestational trophoblastic disease (GTD). It is more likely than other types of GTD to grow rapidly and spread to the uterus organs.

Half of all gestational choriocarcinomas begin to shave as a molar pregnancies. Approximately one-fourth of development occurs in abortion (spontaneous abortion), intentional abortion, or tubal pregnancy (the fetus develops in the fallopian tube instead of uterus). After normal pregnancy and delivery, another quarter (25%) develops.

Rarely, choriocarcinomas that are not related to pregnancy can develop. These can be found in areas other than uterus, and it can occur in both men and women. They can grow in the ovaries, testicles, chest, or abdomen. In these cases, choriocarcinoma is usually mixed with other types of cancers, in which there is a type of cancer called mixed germ cell tumor.

These tumors are not considered gestational (related to pregnancy) and are not discussed in this document. Non-gestational choriocarcinoma may be less reactive for chemotherapy and can be less favorable forecast (approach) than gestational choriocarcinoma. For more information about these tumors, see ovarian cancer and testicular cancer.

Placental-site trophoblastic tumor

Placental-site trophoblastic tumor (PSTT) is a very rare form of GTD where the placenta adds to the uterus layer. This tumor usually develops after normal pregnancy or miscarriage, but it can also develop after the removal of complete or partial mole.

Most PSTTs do not spread in other sites in the body. But these tumors have the tendency to increase the uterus muscle layer (attack).

Most forms of GTD are very sensitive to chemotherapy drugs, but not PSTT. Instead, they are treated with surgery to completely remove the disease.

Epithelioid trophoblastic tumor

Epithelioid trophoblastic tumor (ETT)  is a very rare type of gestational trophoblastic disease that can be difficult to diagnose. ETT was called an atypical choriocarcinoma because cells look like choriocarcinoma cells under the microscope, but now it is considered to be a different disease. Because it can grow in the uterus, it can sometimes be confused with cervical cancer. Like placental-site trophoblastic tumors, ETT often occurs after a full-term pregnancy, but ETT may occur several years after pregnancy. In addition, like placental-site trophoblastic tumors, ETT does not respond very well to chemotherapy drugs, so the main treatment is surgery. When it is diagnosed, it can already be metastasized, in which there is a poorer prognosis (outlook).