After an extragonadal germ cell tumor has been diagnosed, tests are done to find out if cancer cells have spread to other parts of the body.

The extent or spread of cancer is usually described as stages. For extragonadal germ cell tumors, prognostic groups are used instead of stages. The tumors are grouped according to how well the cancer is expected to respond to treatment. It is important to know the prognostic group in order to plan treatment.

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 breast cancer spreads to the bones, the cancer cells in the bones are actually breast cancer cells. The disease is metastatic breast cancer, not bone cancer.

The following prognostic groups are used for extragonadal germ cell tumors:

Good prognosis

A nonseminoma extragonadal germ cell tumor is in the good prognosis group if:

• the tumor is in the back of the abdomen; and
• the tumor has not spread to organs other than the lungs; and
• the levels of tumor markers AFP and β-hCG are normal and LDH is slightly above normal.

A seminoma extragonadal germ cell tumor is in the good prognosis group if:

• the tumor has not spread to organs other than the lungs; and
• the level of AFP is normal; β-hCG and LDH may be at any level.

Intermediate prognosis

A nonseminoma extragonadal germ cell tumor is in the intermediate prognosis group if:

• the tumor is in the back of the abdomen; and
• the tumor has not spread to organs other than the lungs; and
• the level of any one of the tumor markers (AFP, β-hCG, or LDH) is more than slightly above normal.

A seminoma extragonadal germ cell tumor is in the intermediate prognosis group if:

• the tumor has spread to organs other than the lungs; and
• the level of AFP is normal; β-hCG and LDH may be at any level.

Poor prognosis

A nonseminoma extragonadal germ cell tumor is in the poor prognosis group if:

• the tumor is in the chest; or
• the tumor has spread to organs other than the lungs; or
• the level of any one of the tumor markers (AFP, β-hCG, or LDH) is high.

Seminoma extragonadal germ cell tumor does not have a poor prognosis group.