Choriocarcinomas

ALSO KNOWN AS: Chorioblastomas, trophoblastic tumors, chorioepitheliomas, gestational trophoblast neoplasia, gestational trophoblastic disease

RELATED CONDITIONS: Invasive mole

DEFINITION: One of the most dangerous germ-cell cancers, choriocarcinoma is a quick-growing cancer that occurs in a woman’s uterus after a pregnancy, miscarriage, or spontaneous abortion. This cancer arises from trophoblastic cells of the placenta and mimics the development of normal placental tissue. The cancer is usually invasive (metastatic), growing so fast that the original tumor outgrows its blood supply and dies, leaving behind only a small scar. It metastasizes early to the lungs, liver, and brain for unknown reasons.

Risk factors: Pregnant women are at risk.

Etiology and the disease process: Choriocarcinoma is an uncommon cancer that is associated with pregnancy. Choriocarcinomas result from genetic damage to a germ cell—the cancer forms in the trophoblast (placental) cells surrounding the baby. About half of all choriocarcinomas arise from a hydatidiform mole, also known as a molar pregnancy, in which a nonviable embryo implants and rapidly grows within the mother’s uterus. Approximately one-quarter of choriocarcinomas occur after pregnancy, which has resulted in the delivery of a child. The remainder of cases occurs after an abortion, ectopic pregnancy, or genital tumor. Most choriocarcinomas form inside the reproductive organs, such as the testes or ovaries, especially in young adults. A few choriocarcinomas arise in sites outside the reproductive organs (extragonadal tumors); these are usually found in young adults and are more common in men.

Incidence: In the mid-2020s, choriocarcinoma occurred in approximately 0.1 percent of all pregnancies or fewer than seven in 100,000. Choriocarcinoma is more common in Asian Americans than Black Americans and least common in White Americans. Choriocarcinoma has been shown to occur following hydatidiform mole (50 percent), normal-term pregnancy (25 percent), and spontaneous abortion (25 percent).

Symptoms: The symptoms of choriocarcinoma vary, depending on where the tumor originates and where it spreads. If the cancer is in the uterus, the most common symptom is bleeding. Cancers in the ovary often have only subtle signs, such as widening the waistline or pain. Choriocarcinomas that spread to other organs may reveal their presence due to the bleeding or complications from bleeding that occur in their presence. In the brain, this bleeding can cause a stroke. Additional symptoms may include irregular vaginal bleeding, uneven swelling of the uterus, persistently high human chorionic gonadotropin (HCG) levels, or localized pain.

Screening and diagnosis: Most choriocarcinomas produce human chorionic gonadotropin, a hormone normally found only during pregnancy. The presence of HCG in the blood can help diagnose this cancer and monitor the success of treatment. Choriocarcinomas are usually referred to a doctor specializing in cancer treatment (an oncologist). To diagnose this tumor, the doctor will do a physical examination and examine the internal organs with X-rays or ultrasounds. Choriocarcinomas may not be biopsied before being treated because they tend to bleed heavily. Choriocarcinomas can be detected using ultrasound, X-rays, computed tomography (CT), magnetic resonance imaging (MRI) scans, or positron emission tomography (PET) scans.

Treatment and therapy: After making the initial diagnosis, the oncologist will take a careful history and perform an examination to rule out metastasis (spread to other organs). Chemotherapy is the treatment of choice. Choriocarcinoma is one of the tumors that is most sensitive to chemotherapy. The cure rate, even for metastatic choriocarcinoma, is about 94 percent. Almost all patients without metastases can be cured; however, metastatic disease to the kidneys, liver, or brain can be fatal. The chemotherapy regimen is generally EMA-CO: etoposide, methotrexate, actinomycin D, cyclosphosphamide, and vincristine (Oncovin). A hysterectomy (surgical removal of the uterus) is rarely required; however, a hysterectomy may be offered to patients over forty years of age or those desiring sterilization. It may be required for those with severe infection and uncontrolled bleeding.

Prognosis, prevention, and outcomes: No known means of prevention exist; however, early detection of the symptoms and prompt medical treatment can improve the odds of survival. Although careful monitoring after the removal of a hydatidiform mole or the termination of pregnancy may not prevent the development of choriocarcinoma, it is essential in the early identification of the condition, which improves outcome. The prognosis for choriocarcinomas in the uterus is very good. However, these tumors have often spread throughout the body. Still, women who have had choriocarcinomas often go on to have normal pregnancies and deliveries. Choriocarcinomas in sites other than the uterus have a poorer prognosis. These tumors tend to spread quickly and do not always respond well to chemotherapy. Although treatment can be effective, the outcome usually depends on how widely the cancer is dispersed. Generally, the prognosis is worse if the tumor can be found in the liver or brain or if HCG levels are high. Five-year survival rates for choriocarcinomas depend on the type and level of metastasis; however, they are generally between 70 and 80 percent. In cases where the cancer is confined to the uterus and the patient undergoes chemotherapy, survival rates near 100 percent.

In the 2020s, options for treatment for gestational trophoblastic diseases, such as choriocarcinomas, have progressed. Because the disease is imminently curable, at rates of almost 100 percent, ongoing efforts are now focused on improved early detection. Ultrasounds and genetic profiling assist in early detection. Immunotherapies and antiangiogenic therapies have also improved diagnostic rates.

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