Predicting radiological regression in benign breast hyperplasia: the prolactin-to-estradiol ratio as a prognostic biomarker

Background: While benign mammary hyperplasia frequently undergoes spontaneous regression, clinicians currently lack validated serological biomarkers for personalized surveillance strategies. Objective: To evaluate whether the serum prolactin-to-estradiol ratio [PER; prolactin (ng/mL) ÷ estradiol (pg/mL)] can predict radiological regression in benign hyperplasia. Methods: This retrospective cohort study (January 2020-December 2024) enrolled women (18-55 years) with biopsy-confirmed ductal or lobular hyperplasia. Baseline fasting prolactin and estradiol were measured using duplicate electrochemiluminescence immunoassays (WHO-traceable) from routine clinical samples. Follow-up biopsies were performed only when imaging triggers were met. Multivariable logistic regression and interval-censored Cox models assessed associations with demographic, reproductive, and lesion covariates. Performance was evaluated using C-statistics, calibration, ROC analysis, and decision curves. Results: = 0.042). Conclusion: Low PER independently and reliably predicts spontaneous regression of benign breast hyperplasia. External validation studies and point-of-care assay development are needed before clinical implementation.