What is a pregnancy-associated cancer?

Matthew Schlumbrecht, MD, is gynecologic oncologist at Banner MD Anderson Cancer Center.

Question: What is a pregnancy-associated cancer?

Answer: The placenta is tissue that nourishes a developing fetus during pregnancy. When placental tissue grows abnormally, it causes a condition called gestational trophoblastic disease (GTD). GTD is very rare, occurring in less than one out of every 1,000 pregnancies. In most cases, GTD is benign, but in some cases it can progress to cancer.

When the placenta grows abnormally but is not cancer, the pregnancy is called a molar pregnancy. Molar pregnancies usually end in miscarriage. In most cases, a molar pregnancy can be treated easily by removing the abnormal placental tissue with a procedure called dilatation and curettage (D&C).

If the placental tissue turns into cancer, chemotherapy is usually required. A hysterectomy, or removal of the uterus, may be recommended. Fortunately, cure rates with chemotherapy are very high.

Symptoms of GTD include abnormal bleeding in the birth canal, no movement or heartbeat from the developing fetus, or a uterus that is either too big or too small for the age of the fetus. A woman may experience extremely severe morning sickness or very high blood pressure but these are not typical.

Unfortunately, no one knows what causes GTD, but there are a few well known risk factors. Women younger than 20 years old or older than 40 years old are more vulnerable to the condition. Other risk factors include a prior history of GTD, not enough nutrients like folate or beta-carotene in the diet, and being of Asian descent.

All women should seek medical care during their pregnancies. Obstetricians are skilled at detecting GTD, and can refer patients to an oncologist if necessary.