Prediction of persistent gestational trophobalstic neoplasia: the role of hCG level and ratio in 2 weeks after evacuation of complete mole.

OBJECTIVE

The aim of this study was to determine whether or not the serum human chorionic gonadotropin (hCG) level and ratio during 2 weeks after evacuation is predictive of persistent gestational trophoblastic neoplasia (GTN) in patients with complete molar pregnancies.

METHODS

Between January 2000 and June 2010, a total of 467 patients with complete molar pregnancies were diagnosed. Seventeen patients, who had prophylactic chemotherapy and in whom insufficient data were available, were excluded. A receiver operating characteristic curve was used to determine the most useful predictive factor for persistent GTN and multivariate logistic regression was used for analyses.

RESULTS

Persistent GTN was diagnosed in 109 of the 450 patients (24.2%) on the basis of the 2000 FIGO criteria. The optimal cut-off point for hCG 1 and 2 weeks after evacuation was 6400 mIU/mL (sensitivity, 54.1%; specificity, 65.1%) and 2400 mIU/mL (sensitivity, 64.2%; specificity, 78.3%), respectively. The optimal cut-off point for the ratio of pre-evacuation hCG to hCG 2 weeks after evacuation was 30 (sensitivity, 63.3%; specificity, 86.5%). Based on multivariate analysis, this ratio<30 was an independent predictive factor for persistent GTN (odds ratio=6.885; 95% confidence interval, 4.006-11.832; P<0.001).

CONCLUSIONS

The decline ratio in hCG level 2 weeks after evacuation in patients with complete molar pregnancies is the most reliable predictor of persistent GTN. Our analysis may allow clinicians to stratify risk in patients with complete molar pregnancies and to provide more accurate counseling based on the hCG levels obtained 2 weeks after evacuation.