The doctor inserts a probe into the rectum to check your prostate for abnormal areas. The probe sends out sound waves that people cannot hear (ultrasound). The waves bounce off the prostate. A computer uses the echoes to create a picture called a sonogram.

Biopsy

A biopsy is the removal of tissue to look for cancer cells. It’s the only sure way to diagnose prostate cancer. The doctor inserts needles through the rectum into the prostate. The doctor removes small tissue samples (called cores) from many areas of the prostate. Transrectal ultrasound is usually used to guide the insertion of the needles. A pathologist checks the tissue samples for cancer cells.

Grading

If cancer cells are found, the pathologist studies 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. Doctors use tumor grade along with your age and other factors to suggest treatment options.

One system of grading is with the Gleason score. Gleason scores range from 2 to 10. To come up with the Gleason score, the pathologist uses a microscope to look at 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). If there is a second most common pattern, the pathologist gives it a grade of 1 to 5, and adds the two most common grades together to make the Gleason score. If only one pattern is seen, the pathologist counts it twice. For example, 5 + 5 = 10.

A high Gleason score (such as 10) means a high-grade prostate tumor. High-grade tumors are more likely than low-grade tumors to grow quickly and spread.

Staging

If the biopsy shows that you have cancer, your doctor needs to learn the extent (stage) of the disease to help you choose the best treatment. Staging is a careful attempt to find out whether the tumor has invaded nearby tissues, whether the cancer has spread and, if so, to what parts of the body.

The process used to find out if cancer has spread within the prostate or to other parts of the body is called staging. The information gathered from the staging process determines the stage of the disease. It is important to know the stage in order to plan treatment. The following tests and procedures may be used in the staging process:

• Radionuclide bone scan: A procedure to check if there are rapidly dividing cells, such as cancer cells, in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in the bones and is detected by a scanner.
• MRI (magnetic resonance imaging): A procedure that uses a magnet, radio waves, and a computer to make a series of detailed pictures of areas inside the body. This procedure is also called nuclear magnetic resonance imaging (NMRI).
• Pelvic lymphadenectomy: A surgical procedure to remove the lymph nodes in the pelvis. A pathologist views the tissue under a microscope to look for cancer cells.
• CT scan (CAT scan): A procedure that makes a series of detailed pictures of areas inside the body, taken from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be injected into a vein or swallowed to help the organs or tissues show up more clearly. This procedure is also called computed tomography, computerized tomography, or computerized axial tomography.
• Seminal vesicle biopsy: The removal of fluid from the seminal vesicles (glands that produce semen) using a needle. A pathologist views the fluid under a microscope to look for cancer cells.

Metastasis (Cancer Spreading)

There are three ways that cancer spreads in the body:

• Through tissue. Cancer invades the surrounding normal tissue.
• Through the lymph system. Cancer invades the lymph system and travels through the lymph vessels to other places in the body.
• Through the blood. Cancer invades the veins and capillaries and travels through the blood to other places in the body.

When cancer cells break away from the primary (original) tumor and travel through the lymph or blood to other places in the body, another (secondary) tumor may form. This process is called metastasis. The secondary (metastatic) tumor is the same type of cancer as the primary tumor.

When prostate cancer spreads, it's often found in nearby lymph nodes. If cancer has reached these nodes, it also may have spread to other lymph nodes, the bones, or other organs. 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's treated as prostate cancer, not bone cancer. Doctors call the new tumor "distant" or metastatic disease.

Stages

These are the stages of prostate cancer:

Stage I:  In stage I, cancer is found in the prostate only. It cannot be felt during a digital rectal exam and is not visible by imaging. It is usually found accidentally during surgery for other reasons, such as benign prostatic hyperplasia. The Gleason score is low. Stage I prostate cancer may also be called stage A1 prostate cancer.

Stage II: In stage II, cancer is more advanced than in stage I, but has not spread outside the prostate. The Gleason score can range from 2-10. Stage II prostate cancer may also be called stage A2, stage B1, or stage B2 prostate cancer.

Stage III: In stage III, cancer has spread beyond the outer layer of the prostate to nearby tissues. Cancer may be found in the seminal vesicles. The Gleason score can range from 2-10. Stage III prostate cancer may also be called stage C prostate cancer.

Stage IV: In stage IV, cancer has metastasized (spread) to lymph nodes near or far from the prostate or to other parts of the body, such as the bladder, rectum, bones, liver, or lungs. Metastatic prostate cancer often spreads to the bones. The Gleason score can range from 2-10. Stage IV prostate cancer may also be called stage D1 or stage D2 prostate cancer.