How to Use FIGO Scoring System in Clinical Practice
The FIGO (International Federation of Gynecology and Obstetrics) scoring system is essential for risk stratification and treatment planning in gestational trophoblastic neoplasia (GTN), with scores ≤6 indicating low-risk disease treatable with single-agent chemotherapy and scores ≥7 requiring multi-agent chemotherapy due to high risk of resistance to single-agent therapy. 1
Understanding the FIGO 2000 Scoring System for GTN
The FIGO scoring system evaluates eight prognostic factors:
| Prognostic Factor | Score 0 | Score 1 | Score 2 | Score 4 |
|---|---|---|---|---|
| Age (years) | <40 | ≥40 | - | - |
| Antecedent Pregnancy (AP) | Mole | Abortion | Term | - |
| Interval (end of AP to chemotherapy in months) | <4 | 4-6 | 7-12 | >12 |
| hCG (IU/l) | <10³ | 10³-10⁴ | 10⁴-10⁵ | >10⁵ |
| Number of Metastases | 0 | 1-4 | 5-8 | >8 |
| Site of Metastases | Lung | Spleen and kidney | GI tract | Brain and liver |
| Largest Tumor Mass | - | 3-5 cm | >5 cm | - |
| Prior Chemotherapy | - | - | Single drug | >2 drugs |
Step-by-Step Application of FIGO Scoring
Patient Assessment:
- Obtain complete history including antecedent pregnancy type and interval
- Measure serum hCG levels
- Perform physical examination
- Conduct appropriate imaging (pelvic ultrasound, chest X-ray, and additional imaging as indicated)
Score Calculation:
- Assign appropriate points for each of the eight prognostic factors
- Sum the individual scores to obtain the total FIGO score
Risk Classification:
- Low-risk disease: FIGO score 0-6
- High-risk disease: FIGO score ≥7
Treatment Decision:
- Low-risk (0-6): Single-agent chemotherapy (methotrexate or actinomycin D)
- High-risk (≥7): Multi-agent chemotherapy (typically EMA-CO regimen)
- Ultra-high-risk (≥13): Consider low-dose etoposide and cisplatin induction before standard therapy 2
Clinical Implications of FIGO Scoring
Low-Risk Disease (Score 0-6)
- Primary treatment with single-agent chemotherapy (methotrexate or actinomycin D)
- Approximately 60-70% will achieve remission with first-line single-agent therapy 3
- Monitor hCG levels weekly until normal, then monthly for 6-12 months
High-Risk Disease (Score ≥7)
- Requires multi-agent chemotherapy upfront
- Treatment at specialized centers is strongly recommended
- More intensive monitoring and supportive care needed
Special Consideration: FIGO Score ≥13
- Patients with scores ≥13 have significantly higher mortality (38.4% 5-year mortality rate) 2
- These patients account for over 50% of GTN-related deaths
- Consider low-dose etoposide and cisplatin induction therapy to reduce early death risk
- Always manage at highly specialized GTN treatment centers
Important Clinical Nuances
Predictors of Single-Agent Resistance
Even within the low-risk category, certain factors predict resistance to single-agent therapy:
- Pretreatment hCG >10,000 IU/L (especially >100,000 IU/L)
- Interval >7 months since antecedent pregnancy
- Tumor size >5 cm
- Antecedent term pregnancy
- Presence of ≥5 metastases 4
Simplified Alternative Models
Recent research suggests that a simplified model using only five factors (age, pretreatment hCG, number of metastases, antecedent pregnancy type, and interval) may be equally effective for risk stratification 4, 5. However, the complete FIGO system remains the standard of care until further validation.
FIGO Score 5-6 Subgroup Analysis
For patients with FIGO scores of 5-6, consider primary multi-agent chemotherapy if they have:
- Metastatic disease AND choriocarcinoma histology
- Metastatic disease OR choriocarcinoma with hCG ≥149,000 IU/L
- No metastases and no choriocarcinoma but hCG ≥411,000 IU/L 3
Monitoring Response
- Weekly hCG measurements until normal for 3 consecutive weeks
- Continue treatment for 2-3 additional cycles after hCG normalization
- Monthly hCG monitoring for 12 months after completion of therapy
- Resistance to therapy is defined as plateau or rise in hCG levels during treatment
Common Pitfalls to Avoid
- Incomplete staging: Ensure all eight factors are evaluated before determining the FIGO score
- Delayed treatment: Promptly initiate appropriate therapy based on risk classification
- Inadequate follow-up: Regular hCG monitoring is essential to detect resistance early
- Failure to recognize ultra-high-risk patients: Scores ≥13 require specialized management
- Inappropriate treatment setting: High-risk patients should be treated at specialized centers
Remember that while the FIGO scoring system is valuable for risk stratification, clinical judgment remains important, particularly for patients with borderline scores or unusual presentations.