Tamoxifen is used to treat which type of cancer?

• A. Prostate cancer
• B. Ovarian cancer
• C. Estrogen receptor positive (ER+) metastatic breast cancer
• D. Lymphoma

Answer: (C)

Estrogen receptor signaling drives growth in cancers that express the estrogen receptor, so blocking that pathway can slow or stop their progression. Tamoxifen is a selective estrogen receptor modulator that binds to estrogen receptors in breast tissue and acts as an antagonist, preventing estrogen from stimulating cancer cell growth. This makes it effective for estrogen receptor positive (ER+) metastatic breast cancer, where the cancer has spread but still relies on estrogen signaling. It isn’t a standard treatment for cancers driven by other pathways, such as prostate cancer (which relies on androgens), ovarian cancer in general, or lymphoma (a hematologic cancer not driven by estrogen receptor signaling). In ER+ breast cancer, tamoxifen helps control disease by cutting off the estrogen signal that the cancer cells depend on, with possible side effects like hot flashes and risks related to endometrial changes or clotting.