American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the initial treatment for patients with estrogen receptor-positive breast cancer with bone metastases after a long disease-free interval?

1. Chemotherapy

2. An aromatase inhibitor

3. Radiation therapy

4. Ovarian suppression

The correct answer is: An aromatase inhibitor

The initial treatment for patients with estrogen receptor-positive breast cancer who have developed bone metastases after a long disease-free interval is an aromatase inhibitor. This choice is appropriate because aromatase inhibitors are effective in managing hormone receptor-positive breast cancer by lowering estrogen levels in the body. In postmenopausal women, the estrogen produced by the ovaries is minimal, so aromatase inhibitors play a crucial role in inhibiting the aromatase enzyme, which converts androgens into estrogen in peripheral tissues. Since the cancer is estrogen receptor-positive, this means that the cancer cells require estrogen for growth, and reducing estrogen levels can help slow down or halt the progression of the disease. Aromatase inhibitors are well tolerated and are often preferred for this specific patient population, especially in cases where the patients are asymptomatic from the bone metastasis and not presenting with significant visceral disease. In contrast, chemotherapy is typically reserved for more aggressive disease or when there is a rapid progression of cancer, while radiation therapy is more focused on symptom management in cases of bone pain due to metastases rather than systemic treatment. Ovarian suppression might be beneficial in premenopausal women who still produce significant levels of estrogen, but in the context of a postmenop