Which Estrogen Antagonist medication is used to treat breast cancer and is known to cause crystalline retinopathy as well as whorl keratopathy?

Which Estrogen Antagonist medication is used to treat breast cancer and is known to cause crystalline retinopathy as well as whorl keratopathy?

• A. Tamoxifen
• B. Raloxifene
• C. Anastrozole
• D. Letrozole

Answer: (A)

Tamoxifen acts as a selective estrogen receptor modulator, blocking estrogen signaling in breast tissue to treat estrogen receptor–positive breast cancer. It is the agent most classically linked to ocular toxicity of crystalline retinopathy and whorl keratopathy: the drug or its metabolites can deposit in ocular tissues, producing crystalline deposits in the retina and vortex (whorl) patterns in the cornea with long-term use. Raloxifene is another SERM but is used mainly for osteoporosis or risk reduction and has a different ocular risk profile. Anastrozole and letrozole are aromatase inhibitors that lower estrogen levels rather than antagonize the receptor, and they are not associated with these specific eye findings.

Tamoxifen acts as a selective estrogen receptor modulator, blocking estrogen signaling in breast tissue to treat estrogen receptor–positive breast cancer. It is the agent most classically linked to ocular toxicity of crystalline retinopathy and whorl keratopathy: the drug or its metabolites can deposit in ocular tissues, producing crystalline deposits in the retina and vortex (whorl) patterns in the cornea with long-term use. Raloxifene is another SERM but is used mainly for osteoporosis or risk reduction and has a different ocular risk profile. Anastrozole and letrozole are aromatase inhibitors that lower estrogen levels rather than antagonize the receptor, and they are not associated with these specific eye findings.