What is the key difference between LHRH agonist and LHRH antagonist therapies? A. LHRH antagonists are associated with mood changes. B. LHRH agonists may cause a temporary tumor flare. C. LHRH antagonists are associated with lean muscle loss D. LHRH agonists are associated with heart failure.
The correct answer and explanation is:
The correct answer is:
B. LHRH agonists may cause a temporary tumor flare.
Explanation:
Luteinizing hormone-releasing hormone (LHRH) agonists and LHRH antagonists are commonly used in the treatment of hormone-sensitive cancers, such as prostate cancer and breast cancer, by reducing the production of sex hormones like testosterone and estrogen. However, they work through different mechanisms, leading to distinct clinical effects.
LHRH Agonists:
LHRH agonists (e.g., leuprolide, goserelin) initially stimulate the LHRH receptors in the pituitary gland, leading to a temporary increase in luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This surge results in a temporary increase in testosterone or estrogen levels before suppression occurs. This transient rise in hormones can lead to a tumor flare, especially in prostate cancer patients, where increased testosterone can exacerbate symptoms like bone pain or urinary obstruction before the eventual decline in hormone levels. To mitigate this effect, anti-androgens are often prescribed during the initial weeks of treatment.
LHRH Antagonists:
LHRH antagonists (e.g., degarelix, relugolix) bind directly to LHRH receptors and immediately block LH and FSH release, causing a rapid reduction in testosterone or estrogen levels without an initial surge. Because of this mechanism, LHRH antagonists do not cause tumor flare, making them preferable in situations where an immediate hormonal blockade is required, such as in patients with advanced prostate cancer at risk of complications from an initial hormone surge.
Clinical Implications:
- LHRH agonists can cause a temporary tumor flare due to the initial hormone surge.
- LHRH antagonists avoid tumor flare and provide immediate suppression of hormone levels.
- Both classes of drugs are associated with cardiovascular risks, bone density loss, and metabolic changes, but their immediate effects on hormone suppression differ.
Thus, the key difference is that LHRH agonists may cause a temporary tumor flare (Answer B).
Now, I will generate an image representing the concept.
Here is the medical illustration comparing LHRH agonist and LHRH antagonist therapies. The image visually represents the key difference in testosterone suppression and tumor flare effects between these treatments. Let me know if you need any modifications or additional details!
