Bone metastases typically originate from which primary sites?

• A. Kidney, liver, brain
• B. Skin, thyroid, colon
• C. Breast, Lung, Prostate
• D. Ovarian, pancreas, stomach

Answer: (C)

Bone metastases come from cancers that spread through the bloodstream to the bone marrow. In adults, the most common primaries that seed bone are breast, prostate, and lung cancers. The axial skeleton—spine, pelvis, ribs—is a frequent target because it has rich red marrow and substantial blood flow, making it easier for cancer cells to lodge there. Prostate cancer typically produces osteoblastic (sclerotic) lesions, breast cancer can be mixed or osteolytic/osteoblastic, and lung cancer is often osteolytic. Among the given options, breast, lung, and prostate together account for the largest share of bone metastases, which is why this combination is the best answer. Other cancers listed tend to metastasize to liver, lungs, peritoneum, or brain more often than to bone.