Gynecology Topic 47. Choriocarcinoma

I. Definition and Etiology

Definition

• Choriocarcinoma: Highly malignant gestational trophoblastic neoplasia arising from trophoblastic tissue.
• Histology: Malignant cytotrophoblasts and syncytiotrophoblasts, with no chorionic villi.
• β-hCG is usually markedly elevated because syncytiotrophoblast produces hCG.
• Highly vascular tumor → Early hematogenous spread and high bleeding risk.

Etiology / Antecedent Pregnancy

• Can follow any gestational event.
• After hydatidiform mole: About 50%.
• After normal term pregnancy: About 25%.
• After spontaneous/induced abortion or ectopic pregnancy: About 25%.
• May present weeks to months after pregnancy; rarely years later.

II. Clinical Features and Spread

Clinical Features

• Abnormal uterine bleeding: Postmolar, postpartum or postabortion.
• Persistent/rising or markedly elevated β-hCG.
• Amenorrhea or pregnancy-like symptoms due to high hCG.
• Often presents with metastatic symptoms rather than a clear uterine mass.

Metastatic Disease

• Main route: Hematogenous spread.
• Common sites: Lungs most frequent, vagina, brain, liver; less commonly kidney and GI tract.
• Vagina: Blue-purple vascular nodule → Heavy vaginal bleeding risk.
• Lungs: Cough, dyspnea, chest pain, hemoptysis; cannonball lesions may be seen.
• Brain: Headache, seizures, focal neurologic deficits, altered consciousness.
• Liver: Right upper quadrant pain, jaundice, intra-abdominal bleeding risk.

III. Diagnosis and Staging

Laboratory and Imaging

• Quantitative serum β-hCG: Central diagnostic and follow-up marker.
• CBC, renal function, liver function and coagulation tests for baseline/bleeding/chemotherapy planning.
• Thyroid function if hCG is very high or thyrotoxicosis symptoms are present.
• Pelvic ultrasound: Uterine lesion, myometrial invasion clues or retained molar tissue.
• Chest X-ray/CT: Lung metastasis screen.
• Abdominal/pelvic CT or MRI: Liver, kidney and pelvic disease.
• Brain CT/MRI: Neurologic symptoms, high-risk disease or lung metastases depending on protocol.

Biopsy / Curettage

• Biopsy and curettage are usually not recommended for suspected choriocarcinoma.
• Reason: Tumor is highly vascular → Severe hemorrhage risk.
• Diagnosis is often clinical: Antecedent pregnancy + abnormal β-hCG + imaging/metastatic pattern.

Staging and Risk

• FIGO stage: I uterus; II genital structures; III lungs; IV other distant sites such as brain/liver.
• WHO/FIGO risk score uses age, antecedent pregnancy, interval, β-hCG, tumor size, metastasis site/number and previous chemotherapy.
• Low-risk GTN: Score 0-6.
• High-risk GTN: Score >=7 or stage IV disease.

IV. Treatment

Chemotherapy

• Choriocarcinoma is highly chemosensitive; manage with a specialist GTD/oncology center when possible.
• Do not delay chemotherapy for tissue diagnosis when clinical diagnosis is clear.
• Non-metastatic/low-risk disease: Single-agent chemotherapy, usually methotrexate or actinomycin D.
• High-risk, high β-hCG or metastatic disease: Multi-agent chemotherapy.
• EMA-CO: Etoposide + methotrexate + actinomycin D alternating with cyclophosphamide + vincristine (Oncovin).
• Monitor β-hCG during therapy; plateau/rise suggests resistance and need to change regimen.

Surgery and Radiotherapy

• Hysterectomy/TAH: Selected localized uterine disease, severe bleeding, no fertility wish, older age or resistant uterine focus.
• Hysterectomy does not replace chemotherapy when metastatic or high-risk disease is present.
• Resection/embolization: Selected resistant metastatic lesion or life-threatening hemorrhage.
• Radiotherapy: Selected brain/liver metastasis or palliation, integrated with chemotherapy.

V. Follow-Up and Prognosis

Follow-Up

• Serial serum β-hCG: Main marker of response and recurrence.
• Monitor frequently during treatment, often weekly or before each chemotherapy cycle.
• After remission: Continue β-hCG surveillance for at least 6-12 months, longer for high-risk disease by protocol.
• Contraception during treatment and surveillance because pregnancy makes β-hCG interpretation impossible.

Prognosis

• Overall prognosis is good with correct treatment; examiner note: about 95% 5-year survival.
• Low-risk/non-metastatic disease has near-complete cure rates.
• Worse prognosis: Brain/liver metastases, very high hCG, long interval from pregnancy, post-term antecedent pregnancy or previous chemotherapy failure.