What is Gestational Trophoblastic Disease?
Gestational trophoblastic disease (GTD) is a group of rare pregnancy-related disorders originating from abnormal trophoblastic (placental) cells, ranging from premalignant conditions like hydatidiform moles to malignant tumors collectively called gestational trophoblastic neoplasia (GTN). 1
Disease Classification
GTD encompasses two main categories based on malignant potential:
Premalignant Forms
- Complete hydatidiform mole (CHM): Diploid, androgenic origin with no fetal tissue, arising from duplication of a single sperm (75-80%) or dispermic fertilization (20-25%) of an "empty" ovum 2
- Partial hydatidiform mole (PHM): Usually triploid (90%) with two paternal and one maternal haploid chromosome sets, typically showing evidence of fetal tissue or fetal red blood cells 2
- Atypical placental site nodules (APSNs): Malignant potential remains unclear 1
Malignant Forms (Gestational Trophoblastic Neoplasia - GTN)
- Invasive mole
- Choriocarcinoma: Highly aggressive with metastatic potential 3
- Placental site trophoblastic tumor (PSTT): Relatively chemotherapy-resistant, usually requires surgery 3
- Epithelioid trophoblastic tumor (ETT): Also relatively chemotherapy-resistant 3
Key Diagnostic Features
GTN diagnosis does not require histological confirmation - it is primarily based on persistent elevation of human chorionic gonadotropin (hCG) after primary treatment 2. However, complete mole, partial mole, atypical PSN, and PSTT/ETT diagnoses do require histological confirmation 2.
Epidemiology and Incidence
The global burden is substantial: approximately 220,000 women are diagnosed annually worldwide, including 22,000 with GTN 1. In the UK, the calculated incidence is 1 in 714 live births 2. Important risk factors include:
- Ethnic variation: Asian women have higher incidence (1 in 387 vs 1 in 752 live births for non-Asian women) 2
- Age extremes: Women <15 years (1 in 500 pregnancies) and >50 years (1 in 8 pregnancies) face significantly elevated risk 2
- After live birth: GTN incidence is approximately 1 in 50,000 2
Clinical Presentation
With widespread first-trimester ultrasound use, patients are now often asymptomatic at diagnosis, though vaginal bleeding remains the most common presenting symptom 4. The clinical presentation has shifted toward earlier detection, resulting in decreased morbidity from uterine evacuation 5.
Prognosis
GTN is highly curable when treated adequately, with cure rates approaching 98% for choriocarcinoma and invasive mole 6. Low-risk GTN achieves nearly 100% overall survival, while high-risk GTN achieves approximately 90% survival with multiagent chemotherapy 5. However, PSTT and ETT still present lower success rates due to relative chemotherapy resistance 6.
Critical Management Principle
Patients benefit significantly from dedicated multidisciplinary teams and referral to specialized GTD centers 1. The 2025 international consensus guidelines established minimum criteria for GTD centers and developed 18 flow diagrams for diagnosis, treatment, and follow-up 1. This specialized approach is crucial because 50% of the global population lives in low- or middle-income countries where diagnostic and treatment options may be limited 1.