What effect does systemic estrogen therapy (ET) typically have on fibroids after menopause?

Systemic estrogen therapy typically stimulates the growth of fibroids after menopause. Estrogen is known to promote cell growth, and since fibroids are composed of smooth muscle and connective tissue that respond to hormonal changes, their growth can be influenced by estrogen levels in the body. After menopause, the natural decline in estrogen levels usually contributes to a reduction in the size of fibroids. However, if systemic estrogen therapy is applied, it can counteract this effect, potentially leading to the enlargement of pre-existing fibroids.

In the context of the other responses, while fibroids may remain unchanged or even shrink under natural circumstances post-menopause, systemic estrogen administration disrupts this typical trend. The notion that they become cancerous is an exaggeration, as fibroids themselves are benign tumors. Thus, the characteristic of systemic ET leading to growth supports why it is recognized that fibroids often grow larger under this treatment.