After gestational trophoblastic neoplasia has been diagnosed, tests are done to find out if cancer has spread from where it started to other parts of the body.

The process used to find out the extent or spread of cancer is called staging, The information gathered from the staging process helps determine the stage of disease. For GTN, stage is one of the factors used to plan treatment.

The following tests and procedures may be done to help find out the stage of the disease:

• Chest x-ray : An x-ray of the organs and bones inside the chest. An x-ray is a type of energy beam that can go through the body onto film, making pictures of areas inside the body.

• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.

• MRI (magnetic resonance imaging) with gadolinium : A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body, such as brain and spinal cord. A substance called gadolinium is injected into a vein. The gadolinium collects around the cancer cells so they show up brighter in the picture. This procedure is also called nuclear magnetic resonance imaging (NMRI).

There are three ways that cancer spreads in the body.

The three ways that cancer spreads in the body are:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor. For example, if gestational trophoblastic neoplasia spreads to the lung, the cancer cells in the lung are actually trophoblast cells. The disease is metastatic gestational trophoblastic neoplasia, not lung cancer.

There is no staging system for hydatidiform moles.

Hydatidiform moles (HM) are found in the uterus only and do not spread to other parts of the body.

The following stages are used for GTN:

Stage I

In stage I, the tumor is in the uterus only.

Stage II

In stage II, cancer has spread outside of the uterus to the ovary, fallopian tube, vagina, and/or the ligaments that support the uterus.

Stage III

In stage III, cancer has spread to the lung.

Stage IV

In stage IV, cancer has spread to distant parts of the body other than the lungs.

The treatment of gestational trophoblastic neoplasia is based on the type of disease, stage, or risk group.

Invasive moles and choriocarcinomas are treated based on risk groups. The stage of the invasive mole or choriocarcinoma is one factor used to determine risk group. Other factors include the following:

• The age of the patient when the diagnosis is made.
• Whether the GTN occurred after a molar pregnancy, miscarriage, or normal pregnancy.
• How soon the tumor was diagnosed after the pregnancy began.
• The level of beta human chorionic gonadotropin (β-hCG) in the blood.
• The size of the largest tumor.
• Where the tumor has spread to and the number of tumors in the body.
• How many chemotherapy drugs the tumor has been treated with (for recurrent or resistant tumors).

There are two risk groups for invasive moles and choriocarcinomas: low risk and high risk. Patients with low-risk disease usually receive less aggressive treatment than patients with high-risk disease.

Placental-site trophoblastic tumor (PSTT) and epithelioid trophoblastic tumor (ETT) treatments depend on the stage of disease.