What is prostate cancer?
Normally in the prostate, as in the rest of the body, there is a continuous turnover of cells, with new cells replacing old dying ones. In cancer the balance between the new and old cells is lost, with many more new cells being made and older ones living longer. Prostate cancer results when there is uncontrolled growth of the cells in the prostate and the growths (clusters of cancer cells) are malignant. Malignant means that the cancer cells can spread to other areas outside the prostate gland such as the seminal vesicles or bladder, by growing out through the outer wall or capsule of the prostate. They may occasionally spread through the blood stream and implant in the bones, especially in the spine.
Finally, cancer cells can also be spread through lymph vessels. These vessels are like a second system of veins except that, instead of blood, they contain a milky fluid that is made up of the cells waste products. Lymph vessels drain via lymph nodes (special bean-shaped filters) that eventually empty back into the blood circulation. During this process the lymph nodes can also be invaded by cancer cells.