Diagnosis & staging
These are tests that may be used to diagnose this type of cancer.
- Pelvic examination
- Blood test to measure the amount of the pregnancy hormone, human chorionic gonadotropin (HCG) in the blood.
- Chest x-ray
- Because of the extensive use of ultrasound during pregnancy, diagnosis usually comes early in gestation.
For more information on tests used to diagnose cancer, see our Recommended Websites, Diagnostic Tests
Types and Stages
- A hydatidiform mole is also called a molar pregnancy.
- It is usually diagnosed within the first 12 weeks of pregnancy.
- A hydatidiform mole can be classified either as complete or partial.
- In a normal conception, half of the baby's genes come from the male sperm and half from the female egg.
- In a complete hydatidiform mole, an empty egg is fertilized by a sperm and the complete genetic content is only from the sperm. A baby does not develop and a mass that looks like grape-like tissue fills the uterus.
- In a partial hydatidiform mole, one egg is fertilized by two sperm and there are three sets of chromosomes instead of the normal two sets. A baby develops, but dies within a few weeks of pregnancy.
- A hydatidiform mole is benign rather than cancerous but it could develop into cancer.
- There is a higher chance of a complete hydatidiform mole developing into an invasive mole or choriocarcinoma than the partial type of hydatidiform mole.
- An invasive mole occurs when hydatidiform mole tissue that remains in the uterus grows into the muscle layer (myometrium).
Placental-site trophoblastic tumour
- A tumour develops from the tissue that started as a hydatidiform mole, or tissue that is still in the uterus after treatment for hydatidiform mole. It can also develop from tissue that remains in the uterus after an abortion or following the delivery of a baby.
- Choriocarcinoma can spread to other parts of the body.
- A placental-site trophoblastic tumour is a very rare type of cancer.
- It starts in the place where the placenta was attached to the muscle of the uterus.
Staging describes the extent of a cancer. The TNM
classification system is used as the standard around the world. In general a lower number in each category means a better prognosis. The stage of the cancer is used to plan the treatment.
T describes the site and size of the main tumour (primary)
N describes involvement of lymph nodes
M relates to whether the cancer has spread (presence or absence of distant metastases)
The disease is confined to the uterus
The disease has spread outside of the uterus to other genital areas
The disease has spread to the lungs
The disease has spread to other parts of the body