This is a single-center, double-blind, double-simulated, positive-controlled, randomized clinical trial to explore the efficacy and safety of external mastalgia-oil versus oral tamoxifen in premenopausal women with severe mastalgia.
Premenopausal females aged ≥ 18 years old
Pre-existing regular menstrual cycle (28 ± 3 days) with mastalgia lasting for at least 6 consecutive menstrual cycles; with severe mastalgia [visual analog scale (VAS) score ≥ 4 for at least 7 days] and without chest wall pain in the baseline menstrual cycle (nonmedicated menstrual cycle)
With breast ultrasound: BI-RADS classification 1-3; if mammography is required: also BI-RADS classification 1-3
Willingness to follow up and complete required tests; ability to complete questionnaires independently or with assistance
With suspected breast disease (e.g., mastitis, malignant breast tumor) other than breast pain or benign breast cysts, or with other malignant tumors
Use of hormonal medications (e.g., oral contraceptives, glucocorticoids, etc.), sex hormone modulators (SERMS, AIs, SERDs, etc.), B vitamins, essential oils, nonsteroidal anti-inflammatory drugs, or higher pain relievers in the past 3 months; use of tamoxifen or analogs in the past 6 months
Prior history of breast surgery (including minimally invasive surgery), history of malignancy, or history of thromboembolism within the last 5 years (history of varicose veins and superficial phlebitis allowed)
Smokers; tamoxifen or essential oils systemic/skin sensitization