What is the reason for multiple bone metastases from prostate cancer? Advanced prostate cancer includes both locally advanced and distant metastases. Locally advanced means that the tumor grows infiltratively inside the prostate organ and protrudes to the outside of the prostate. The distant metastases of prostate cancer are mostly bone metastases, usually the vertebrae, i.e. the vertebrae on the spine, and then the ribs and iliac bones, which in medical terms have obvious osteophilic characteristics. The answer is: the mechanism is unknown, however, there are several doctrines that are still more recognized by everyone. The blood circulation theory proposed by Zhu Shulun Batson of the Department of Urology of Guangdong Provincial Hospital suggests that there is a “portal” venous system between the prostate and the low lumbar vertebrae, which has been confirmed as the Batson venous plexus (vertebral venous plexus). The lack of a valve for venous traffic between the prostatic plexus and the Batson’s plexus increases the chance of prostate cancer metastasizing to the spine. Stephen Paget proposed the “seed and soil” theory, which suggests that distant tumor metastasis is a specific, rather than random, phenomenon. Thus, although prostate cancer cells metastasize throughout the body, this specific biology leads to a tendency for prostate cancer cells to eventually form metastatic foci in the bone rather than in other organs; Yonou et al. According to these two theories, bone metastases are common in prostate cancer, but extraosseous metastases are rare, even in patients with skeletal metastases or terminal prostate cancer. It is important to add that extraosseous metastases of prostate cancer are called jumping metastases, such as liver and lung. This type of metastasis is often under-appreciated, delaying the diagnosis and proper treatment.