The relationship between HRT and breast cancer is complex. Research indicates that the risk varies depending on the type of HRT, duration of use, and individual factors such as age and family history. Estrogen-only HRT appears to have a different risk profile compared to combined HRT (estrogen and progesterone). Combined HRT is generally associated with a higher risk of breast cancer, particularly with long-term use. The risk seems to increase with the duration of therapy and appears to return to baseline levels within a few years after stopping HRT. In contrast, estrogen-only HRT, which is typically prescribed to women who have had a hysterectomy, has shown a less clear association with breast cancer risk, with some studies suggesting a slight increase or no significant risk.
