Choriocarcinoma

Definition

A choriocarcinoma is type of germ cell cancer containing trophoblast cells.

Demographics

Choriocarcinoma is a rare tumor type which, in women, develops in one out of every 40 hydatidiform moles and in one out of 20,000-40,0000 pregnancies in the United States. The incidence of choriocarcinoma is more prevalent in countries such as India (incidence rate of one in every 500-600 pregnancies), Mexico, Paraguay, and Sweden.


African American women have the highest incidence rates of choriocarcinoma and have the lowest survival rates once diagnosed with this cancer. This type of cancer is 5-15 times more likely to be diagnosed in women over the age of 40 than in women under 40 years of age.

Choriocarcinoma that develops in men usually develops as a type of testicular tumor. Choriocarcinoma of the testes is a rare cancer in men. However, this tumor type, which is primarily diagnosed in younger men, is the most common cancer diagnosed inmen between the ages of 15-35 years. This cancer affects white malesmore than males of other racial/ethnic groups.



Description

Choriocarcinomas are cancers that develop from germ cells, cells that ordinarily turn into sperm or eggs. Choriocarcinomas resemble the cells that surround an embryo in the uterus. Most of these cancers form inside the reproductive organs. Some originate in the testes or ovaries, especially in young adults. Others develop in the uterus after a pregnancy or miscarriage-particularly following the presence of a hydatidiform mole. A few choriocarcinomas arise in sites outside the reproductive organs.

Choriocarcinomas are one of the most dangerous germ cell cancers. They usually grow quickly and spread widely. Occasionally, this cancer grows so fast that the original tumor outgrows its blood supply and dies, leaving behind only a small scar.

Causes and symptoms

Choriocarcinomas result from genetic damage to a germ cell.Males with Klinefelter syndrome are especially likely to develop extragonadal germ cell tumors.

The symptoms of a choriocarcinoma vary, depending on where the tumor originates and where it spreads. In the uterus, the most common symptom is bleeding. Other symptoms associated with tumors that have metastasized include purple or blue/black nodules on the lower genital tract tissues, abdominal tenderness, and jaundice if the tumor has spread to the liver. Cancers in the ovary often have only subtle signs such as widening of the waistline or pain.

In the testes, choriocarcinomas can often be felt as small painless lumps.

Choriocarcinomas that spread to other organs may reveal their presence by bleeding. In the brain, this bleeding can cause a stroke.

Examination

Choriocarcinomas are usually referred to an oncologist, a doctor who specializes in cancer treatment. To diagnose this tumor, the doctor will do a physical examination and examine the internal organs with x rays or ultrasound studies.

Tests

Spreading of the cancer is detected with x rays, ultrasound studies, computed tomography (CT), or magnetic resonance imaging (MRI) scans.

Most choriocarcinomas make human chorionic gonadotropin (beta-hCG), 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.

Procedures

Choriocarcinomas are not always biopsied before being treated, because they tend to bleed heavily.

Treatment

Women diagnosed with choriocarcinomas that have not metastasized or who are diagnosed with tumors that are of low risk for metastasis are usually treated with the chemotherapy agent methotrexate. Another chemotherapy drug, actinomycin D, may be used if the patient has been diagnosed with liver dysfunction. Beta-hCG levels are monitored to determine response to therapy.

Women diagnosed with metastatic disease are divided into two groups based on whether or not they are at high risk for treatment failure. Patients who are at lower risk are treated with methotrexate or actinomycin and are typically cured with chemotherapy. Women deemed to be at higher risk are treated with combination chemotherapy. Patients with metastasis to the brain also receive whole brain radiation therapy. Other patients with brain involvement may be treated with stereotactic radiotherapy.A hysterectomy may be required for women who experience vaginal bleeding that cannot be controlled by nonsurgical means.

Currently, there is no consensus as to the best treatment for testicular choriocarinomas. Some chemotherapy agents that may be used include a combination of the drugs bleomycin, etoposide, and cisplatin for four cycles and/or the drugs vinblastine and ifosfamide. However, most choriocarcinomas of the testicles respond poorly to chemotherapy.

Surgery is typically recommended to remove a testicle (or both testicles if cancer has been detected in both) utilizing a surgical procedure termed radical inguinal orchiectomy.

Prognosis

The prognosis for choriocarcinomas in the uterus is very good. Although these tumors often spread throughout the body, chemotherapy results in a cure or remission in 75-100% of cases. The probability of a recurrence of choriocarcinoma in women who have been in remission with normal beta-hCG levels for at least one year is very small, typically less than 1%. Women who have had choriocarcinomas often go on to have normal pregnancies and deliveries.

Choriocarcinomas in other sites have a poorer prognosis. These tumors tend to spread quickly and do not respond well to chemotherapy. Although treatment can be effective, the outcome depends on how widely the cancer has metastasized. The prognosis is worse if the cancer can be found in the liver or brain, if hCG levels are high, or if the original tumor developed outside the gonads.

Choriocarcinomas of the testes metastasize early and typically do not respond to chemotherapy or radiation therapy. These cancers have a dismal prognosis with high mortality rates despite aggressive treatment.

Prevention

There is no known means of prevention. Early detection of the symptoms and prompt medical treatment can improve the odds of survival.