American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the main treatment for prostate cancer metastatic to bone?

1. Chemotherapy only

2. A bisphosphonate and radium-223

3. Radiation therapy alone

4. Hormone replacement therapy

The correct answer is: A bisphosphonate and radium-223

The main treatment for prostate cancer that has metastasized to bone focuses on managing both the cancer progression and the associated symptoms, particularly pain, that arise from bone metastases. Combining a bisphosphonate and radium-223 addresses these issues effectively. Bisphosphonates help to strengthen bones and reduce skeletal-related events caused by metastases, such as fractures and severe pain. They work by inhibiting osteoclast-mediated bone resorption, thereby stabilizing the bone structure affected by cancer cells. Radium-223 is a radiopharmaceutical that targets bone metastases specifically, delivering localized radiation to the cancerous cells while minimizing exposure to surrounding healthy tissue. This not only alleviates pain but can also improve survival for patients with symptomatic bone metastases. Although chemotherapy can be a component of prostate cancer treatment, it is not the first-line approach specifically for bone metastases. Radiation therapy alone offers symptomatic relief but does not have the comprehensive benefits of the combination mentioned. Hormone replacement therapy is unrelated to the specific treatment of metastatic prostate cancer, which often involves androgen deprivation rather than replacement. Combining bisphosphonates with radium-223 forms a rational and effective strategy in managing this complex clinical scenario, focusing on both cancer control