## **Core Concept**
Prostate cancer (CA prostate) commonly metastasizes to bones, and the vertebrae are a frequent site for such metastases. This occurs through a hematogenous route, primarily through the venous system.

## **Why the Correct Answer is Right**
The correct answer, , involves the venous system, specifically the Batson's plexus or vertebral venous plexus. Prostate cancer cells can enter this plexus and travel to the vertebral bodies, leading to metastasis. This pathway allows cancer cells to bypass the lungs and liver, which are common sites for filtration and potential trapping of metastatic cells.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because, although arterial spread does occur in cancer metastasis, it is not the primary route for prostate cancer to metastasize to the vertebrae.
- **Option B:** This option is incorrect because lymphatic spread is a common route for many cancers but is not the primary mechanism for prostate cancer to metastasize to the vertebrae directly.
- **Option C:** This option might seem plausible due to direct extension being a mode of spread for some tumors, but it is not the typical mechanism for prostate cancer to metastasize to distant sites like the vertebrae.

## **Clinical Pearl / High-Yield Fact**
A key point to remember is that prostate cancer often metastasizes to bones, particularly the vertebrae, pelvis, and ribs, due to the rich vertebral venous plexus (Batson's plexus) that communicates directly with the prostate venous drainage. This is why vertebral metastases are common in prostate cancer.

## **Correct Answer:** . Venous route (Batson's plexus).