Early Detection of Gestational Trophoblastic Neoplasia Based on Serial Measurement of Human Chorionic Gonadotrophin Hormone in Women with Molar Pregnancy

BACKGROUND: The majority of studies which investigate the predicted power of Human chorionic gonadotropin (hCG) levels to the occurrence of Gestational trophoblastic neoplasia (GTN) considered the effect of a single measurement of hCG or used classical statistical methods without considering the endogenous marker. The aim of this study is to investigate the association between weekly measurements of β-hCG with time to GTN occurring, using a robust Bayesian joint modeling. METHODS: Data of 201 women with a molar pregnancy were considered for this retrospective cohort study. After the first measurement of β-hCG in 48 hours post evacuation of mole, the other titration was performed on a weekly basis until three consecutive normal titers. The association between serial measurements of β-hCG and risk of GTN occurring were assessed by the classic and Bayesian joint modeling and in separate analysis the mixed linear effect and Cox-PH model were used. RESULTS: The mean age (SD) of participants was 26.6 (6.55) year. The GTN was occurred among 14.9% of patients. The association parameter using Bayesian approach was estimated as 1.30 (95% CI: 0.44 to 2.20) which showed one unit increase in the log β-hCG corresponds to the 2.80-times increase in the hazard for the occurrence of GTN (Hazard Ratio: 2.80, 95% CI: 1.55 to 8.98). CONCLUSIONS: Findings of this study revealed that weekly measurements of β-hCG are an important and reliable biomarker to early detection of developing of molar pregnancy to persistent GTN.