Local Spread
Prostate cancer is the result of cells of the prostate (which is a gland located at the base of the penis) growing abnormally quickly, leading to cancer. As the American Cancer Society explains, prostate cancer can spread to other tissues. The first part of this process is local spread of the cancer. Before prostate cancer can spread to other parts of the body, it needs to be able to spread throughout the rest of the prostate tissue. In order to do this the cancer cells need to be able to break down the connective tissue that surrounds the cells. Because cells are held in place by proteins, the cancer cells will have to express other proteins (called proteinases) which will break down the surrounding connective tissue.
Prostate Escape
As the Cancer Biology e-book from the National Institute of Health explains, for prostate cancer cells to spread to other parts of the body they need to be able to escape the prostate tissue, which again requires proteins to be broken down. Once the prostate cancer cells have left the prostate they need to either travel into the lymphatic system (where they can spread to the lymph nodes) or into the bloodstream. In either case the cancer cells have to develop the ability to survive in new environments while they travel throughout the body. If prostate cancer cells travel through the lymphatic system they also need to evade immune cells, which can attack cancer cells and kill them. They may also need to be able to survive with less oxygen and fewer nutrients as they migrate from the prostate.
Metastatic Tumor Formation
Once prostate cancer cells have entered into the lymphatic system or the bloodstream, they need to be able to exit and form new tumors in other organs. Prostate cancer, according to Medline, often spreads to the bones, the lungs or the liver. The cancer cells will need to be able to latch onto the tissue in the organs and then form new blood vessels via a process called angiogenesis. This is necessary so that the newly formed cancer cells are able to get the oxygen and nutrients necessary to grow and form larger tumors. Once prostate cancer has gotten into the lymphatic system or the blood it can spread to any organ to which these migrating cells can make contact.
