Normally about the size of a walnut, the prostate gland is part of the male reproductive system, producing fluid that is released in semen when a man ejaculates. Cancer of the prostate is the third most common cause of death from cancer in all men and the leading cause of cancer deaths in men over 75 years of age, indicates MedlinePlus. The Prostate Specific Antigen test is used to identify men who may have prostate cancer. High PSA levels indicate the need for further testing.
There are several stages, or levels, of prostate cancer, depending on how far the cancer has spread. The system of staging most commonly used is the "TMN" system, where T stands for the extent of the primary tumor, N for whether it has spread to nearby lymph nodes, and M for whether or not the cancer has spread, or metastasized. Once all of the information has been gathered through testing and combined with results of the biopsy, the cancer will be called Stage I, Stage II, Stage III or Stage IV.
Stage I
In Stage I, the cancer is still contained within the prostate. It has not spread to the lymph nodes or any other part of the body, and the patient's PSA score is in a lower range. If the tumor was felt during an exam or seen with ultrasound, it is still small, no bigger than half of one of the two lobes of the prostate.
Stage II
In Stage II, the cancer has still not spread outside the prostate, but the patient's PSA score is higher than in Stage I. This stage is usually divided into Stage IIA and Stage IIB, with the subcategory determined by scores from the PSA and other tests. Additionally, in Stage IIA the cancer is still only in one lobe of the prostate, while in Stage IIB it has often spread to both lobes.
Stage III
In Stage III, the cancer has begun to spread into the outer parts of the prostate. It may also have spread to the seminal vesicles, two small, fluid-filled sacs that are very close to the prostate.
Stage IV
If the cancer has spread even more, into tissue or other organs in the pelvis, it is in Stage IV. It may also have spread into the lymph nodes or to more distant parts of the body. Once the cancer reaches Stage IV, it has often spread into the bones.
