Personalized Prediction of Uterine Fibroid Shrinkage During GnRH Antagonist Treatment via Pretreatment T2-Weighted MRI Signal Intensity.

AIM: To develop and internally validate a pretreatment quantitative magnetic resonance imaging-based predictive model for uterine fibroid volume reduction following gonadotropin-releasing hormone antagonist therapy.

METHODS

In this single-center retrospective study, 106 women with uterine fibroids treated with relugolix underwent pre- and intratreatment magnetic resonance imaging. The dominant fibroid was assessed for T2-weighted imaging fibroid-to-iliopsoas signal intensity ratio, apparent diffusion coefficient, flow voids, and fibroid location. The primary outcome was a ≥ 30% reduction in dominant fibroid volume between pre and intratreatment magnetic resonance imaging. Eight baseline variables were entered into a Least Absolute Shrinkage and Selection Operator-penalized logistic regression model with bootstrap internal validation.

RESULTS

Sixty patients (56.6%) achieved a ≥ 30% volume reduction. In the univariate analyses, a higher T2-weighted imaging signal intensity ratio and location were significantly associated with response. A purely data-driven Least Absolute Shrinkage and Selection Operator model retained two predictors: dichotomized T2-weighted imaging signal intensity ratio and location. A T2-weighted imaging ratio ≥ 2.0 was the strongest positive predictor, whereas subserosal and cervical locations showed negative associations and submucosal location showed a slight positive association relative to intramural fibroids. The model showed moderate discrimination (apparent area under the receiver operating characteristic curve, 0.746; optimism-corrected area, 0.671) with acceptable calibration.

CONCLUSIONS

Quantitative pretreatment T2-weighted imaging (ratio ≥ 2.0) is strongly associated with fibroid volume reduction under gonadotropin-releasing hormone antagonist therapy. An internally validated Least Absolute Shrinkage and Selection Operator-based model incorporating T2-weighted imaging signal intensity and location may aid individualized treatment selection and preoperative planning.