American Board of Internal Medicine (ABIM) Certification Practice Exam

Which antiestrogen treatment is NOT indicated for metastatic breast cancer?

1. Tamoxifen

2. Aromatase inhibitors

3. Megestrol acetate

4. Progesterone therapy

The correct answer is: Progesterone therapy

In the context of treating metastatic breast cancer, progesterone therapy is not typically indicated as an antiestrogen treatment. While progesterone can play a role in treating certain hormone-sensitive cancers, it is not classified as an antiestrogen. The main purpose of progesterone in oncology is often more related to palliative care or managing symptoms rather than directly targeting the estrogen receptors or the pathways involved in breast cancer proliferation. Tamoxifen, aromatase inhibitors, and megestrol acetate are all recognized treatments for hormone receptor-positive metastatic breast cancer. Tamoxifen is a selective estrogen receptor modulator (SERM) that inhibits estrogen activity in breast tissue, making it effective for treatment. Aromatase inhibitors work by reducing estrogen production in the body, which is beneficial in postmenopausal women with hormone receptor-positive disease. Megestrol acetate, while primarily a progestin used for appetite stimulation, also demonstrates some efficacy in breast cancer treatment, specifically in estrogen receptor-positive cases. Overall, the lack of indication for progesterone therapy in this scenario stems from its role not being specifically antiestrogen in nature, which is crucial for managing metastatic breast cancer effectively.