Women receiving oestrogen therapy have an increased risk of developing all of the following cancers, except?
**Core Concept**
Estrogen therapy in women is associated with an increased risk of certain hormone-sensitive cancers due to the stimulation of estrogen receptors. This is particularly relevant for cancers that are known to be influenced by estrogen levels, such as breast cancer and endometrial cancer.
**Why the Correct Answer is Right**
Estrogen therapy promotes the growth and proliferation of estrogen receptor-positive cells, which is a key factor in the development of breast and endometrial cancers. The increased risk is thought to be due to the unopposed stimulation of estrogen receptors in these tissues, leading to uncontrolled cell growth and tumor formation.
**Why Each Wrong Option is Incorrect**
**Option A:** Endometrial cancer - Incorrect because estrogen therapy is actually associated with an increased risk of endometrial cancer, not a decreased risk. The unopposed stimulation of estrogen receptors in the endometrium leads to hyperplasia and an increased risk of cancer.
**Option B:** Ovarian cancer - Incorrect because while ovarian cancer is a hormone-sensitive cancer, the relationship between estrogen therapy and ovarian cancer risk is more complex and not as strongly established as it is for breast and endometrial cancers.
**Option C:** Colorectal cancer - Incorrect because estrogen therapy is not associated with an increased risk of colorectal cancer, and may even have a protective effect against this type of cancer.
**Clinical Pearl / High-Yield Fact**
It's essential to note that the increased risk of cancer associated with estrogen therapy is dose-dependent and varies depending on the duration of therapy. Women receiving estrogen therapy should be closely monitored for any signs or symptoms of cancer, particularly breast and endometrial cancer.
**Correct Answer:** D. Colorectal cancer