OC04.04: Could uterine artery pulsatility index be a predictor of methotrexate resistance in low‐risk gestational trophoblastic neoplasia?

This study assessed in the population of low-risk gestational trophoblastic neoplasia (LR-GTN) patients, whether the uterine artery pulsatility index (UAPI) could be a predictor of resistance to methotrexate chemotherapy (MTX-R). A prospective observational study of 204 LR-GTN (FIGO scores ranged from 0 to 6) from January 2015 to September 2017 at National Hospital of Obstetrics and Gynecology (NHOG). All the patients underwent a single Doppler ultrasound to assess the UAPI before treating with MTX.UAPI was measured in both uterine arteries. The lowest UAPI from either uterine artery was used for analysis, since it is a reflection of the maximal deviation from the normal impedance. The ROC curve of UAPI at the cut-off point 1.2 show moderate predicted probabilities of MTX resistance (AUC = 0.59, sensitivity 71.62% and specificity 48.21%). UAPI, hCG and the largest tumour size were all predictors of MTX-R on univariate analysis. Interestingly, the UAPI remained as a significant independent predictor of MTX-R on multivariate logistic regression analysis. When integrated into the FIGO scores, we discovered 100% of patients with FIGO score ≥5 and UAPI ≤1.2 had MTX-R. UAPI, as an indirect in vivo measure of functional tumour vascularity, could predict the response to MTX-R in LR-GTN patients. Patients with FIGO score of 5-6 and a UAPI<1.2 might be considered to be upstaged and offered combination chemotherapy as the initial regimen rather than MTX. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.