A prostate cancer diagnosis is confirmed by a biopsy. The pathologist studies the tissue samples from the prostate under a microscope to report the grade of the tumor. The grade tells how much the tumor tissue differs from normal prostate tissue. It suggests how fast the tumor is likely to grow.
Tumors with higher grades tend to grow faster than those with lower grades. They are also more likely to spread. You and your doctor carefully evaluate both the effectiveness of the treatment options, as well as their side effects. Factors to consider include the stage, Gleason score, PSA level, your age, any other diseases or conditions you may have, potential side effects of treatments, and your personal preferences.
One system of grading is with the Gleason score. Gleason scores range from 2 to 10. The pathologist grades the tissue based upon the patterns of cells in the prostate tissue. The most common pattern is given a grade of 1 (most like normal cells) to 5 (most abnormal). The pathologist gives the second most common pattern a grade of 1 to 5, and adds the two most common grades together to make the Gleason score. A high Gleason score means a high-grade prostate tumor.
The term "localized prostate cancer" refers to cancer that is confined to the tissue in which it originated (stage I or stage II); meaning that the cancer has not spread to other organs.
Advanced prostate cancer is a later stage cancer that has spread outside of the prostate tissue. When prostate cancer spreads, it is often found in nearby lymph nodes. If cancer has reached these nodes, it may have spread to other lymph nodes and/or organs. Stage III and stage IV prostate cancer may be "locally advanced" (it has spread to areas surrounding the prostate) or metastatic (it has spread to other organs, frequently the bones). In addition, advanced cancer can refer to an earlier stage of prostate cancer that has come back after treatment.
When cancer spreads from its original place to another part of the body, the new tumor has the same kind of abnormal cells and the same name as the primary tumor. For example, if prostate cancer spreads to bones, the cancer cells in the bones are actually prostate cancer cells. The disease is metastatic prostate cancer, not bone cancer. For that reason, it is treated as prostate cancer, not bone cancer. Doctors call the new tumor “distant” or metastatic disease.
Tests to determine if the cancer has spread and to what parts of the body include:
- A small amount of a radioactive substance is injected into a blood vessel. It travels through the bloodstream and collects in the bones. A scanner measures the radiation. A Bone scan may show cancer that has spread to the bones.
- CT scan: An x-ray machine linked to a computer takes a series of detailed pictures. Doctors use CT scans to look for prostate cancer that has spread to lymph nodes and other areas. You may receive contrast material by injection into a blood vessel in your arm or hand, or by enema.
- MRI: A strong magnet linked to a computer is used to make detailed pictures of areas inside your body. An MRI can show whether cancer has spread to lymph nodes or other areas. Sometimes contrast material is used.
These are the stages of prostate cancer:
- Stage I: The cancer can’t be felt during a digital rectal exam, and it can’t be seen on a sonogram. It’s found by chance when surgery is done for another reason, usually for BPH. The cancer is only in the prostate. The grade is G1, or the Gleason score is no higher than 4.
- Stage II: The tumor is more advanced or a higher grade than Stage I, but the tumor doesn’t extend beyond the prostate. It may be felt during a digital rectal exam, or it may be seen on a sonogram.
- Stage III: The tumor extends beyond the prostate. The tumor may have invaded the seminal vesicles, but cancer cells haven’t spread to the lymph nodes.
- Stage IV: The tumor may have invaded the bladder, rectum, or nearby structures (beyond the seminal vesicles). It may have spread to the lymph nodes, bones, or to other parts of the body.