Persistent trophoblastic disease and choriocarcinoma are very rare and are part of a group of tumours called gestational trophoblastic tumours (GTTs).

Persistent trophoblastic disease occurs after a molar pregnancy. If the tissue isn't fully removed during the original treatment, it can become cancerous. Further treatment is then needed to ensure that all the molar tissue is removed.

Choriocarcinoma is a very rare condition that can happen after any pregnancy, but it's more common after a molar pregnancy. It happens when cells left behind after a pregnancy become cancerous.

Who is affected?

Both of these conditions are very rare. If you have had a molar pregnancy, you will be monitored closely in case you do develop either of these conditions.

If you have had a complete molar pregnancy, you have about a 1 in 10 chance (10%) of developing either persistent trophoblastic disease or a choriocarcinoma. For women who have a partial molar pregnancy the risk is 1 in 200 (0.5%).

Outlook

Persistent trophoblastic disease and choriocarcinoma are usually treated with chemotherapy.

As with most types of cancer, the outlook for individual cases will depend on individual circumstances. Overall, 98-100% of women with a GTT are cured.