A prostate is the male sex gland responsible for semen production. It is about the size of a walnut and located below the bladder and in front of the rectum. The prostate is a muscular gland that plays an important role in both sexual and urinary function. As men age, it is normal for the cells in their prostate to change shape and size. These cells can create four types of growth, including:
When abnormal prostate cells grow out of control, they are called cancer cells. These cells may or may not cause symptoms. Some tumors can be felt during a physical exam, while others cannot. Prostate cancer is the most common cancer among men (after skin cancer). In fact, roughly one in nine men will be diagnosed at some point in their lives. If caught early on, before the cancer has spread to other parts of the body, prostate cancer can be treated successfully. The five-year survival rate for localized prostate cancer is 100%.
It is normal for a man's prostate to grow larger as he ages. This is called benign prostatic hyperplasia, or BPH. Men with BPH may find it difficult to urinate because they have extra prostate tissue squeezing their urethra. However, BPH is not cancer and does not lead to cancer.
Prostate cancer may grow into nearby organs or spread to nearby lymph nodes, the small organs around the body that are part of the immune system. In some cases, the cancer spreads to bones or organs in distant parts of the body. This is called metastasis. This type of cancer is more difficult to treat.
Prostatic intraepithelial neoplasia cells, or PINs, do not look like normal prostate cells. PINs are not cancer cells, but they may signal that cancer could form.