Benign breast diseases, contraception and hormone replacement therapy.

Area of Science:

• Gynecology
• Oncology
• Pathology

Background:

• Benign breast disease (BBD) presents a heterogeneous spectrum of lesions.
• Non-proliferative lesions (70%) carry no increased breast cancer risk, typical hyperplasia (26%) a two-fold risk, and atypical hyperplasia (4%) a five-fold risk.
• Data on steroid hormone effects on BBD are derived from observational studies with potential biases.

Purpose of the Study:

• To review the current understanding of the relationship between hormonal factors and benign breast disease.
• To evaluate the impact of oral contraceptives and hormone replacement therapy (HRT) on BBD incidence and clinical presentation.

Main Methods:

• Systematic review of observational studies examining steroid hormone use and benign breast disease.
• Analysis of data regarding oral contraceptive use and HRT effects on BBD incidence, risk, and clinical patterns.

Main Results:

• Oral contraceptives are generally reported to be protective against BBD, though some studies indicate unclear effects.
• Hormone replacement therapy (HRT) shows conflicting results, with some studies reporting increased incidence, others no effect, or a protective effect.
• HRT use does not appear to alter the clinical presentation of BBD in postmenopausal women, with rare reports of cyst or fibroadenoma enlargement.

Conclusions:

• The association between oral contraceptives and BBD risk is predominantly protective.
• Evidence regarding HRT and BBD is inconsistent, but current data do not indicate a significant deleterious effect, even in high-risk individuals.
• Further research is needed to clarify the complex interactions between hormonal therapies and benign breast conditions.