What is the key difference between estrogen-only and combined hormone therapy?

What is the key difference between estrogen-only and combined hormone therapy?

• A. Estrogen alone can increase the risk of uterine cancer; combined therapy includes progestin to reduce this risk
• B. Combined therapy has no risk of uterine cancer
• C. Estrogen alone reduces the risk of uterine cancer
• D. Progestin alone reduces cancer risk

Answer: (A)

Unopposed estrogen stimulates the lining of the uterus. When estrogen is given without a progestin in someone with a uterus, this continuous stimulation can lead to endometrial thickening and, over time, a higher risk of endometrial cancer. Adding a progestin in combined hormone therapy counteracts that effect by thinning the endometrium and promoting shedding, which lowers the cancer risk. So estrogen alone increases uterine cancer risk in people with a uterus, while the progestin in combined therapy reduces that risk. If a person has had a hysterectomy, the uterus is removed, so the endometrial cancer risk tied to unopposed estrogen is no longer a concern.

Unopposed estrogen stimulates the lining of the uterus. When estrogen is given without a progestin in someone with a uterus, this continuous stimulation can lead to endometrial thickening and, over time, a higher risk of endometrial cancer. Adding a progestin in combined hormone therapy counteracts that effect by thinning the endometrium and promoting shedding, which lowers the cancer risk. So estrogen alone increases uterine cancer risk in people with a uterus, while the progestin in combined therapy reduces that risk. If a person has had a hysterectomy, the uterus is removed, so the endometrial cancer risk tied to unopposed estrogen is no longer a concern.