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.

Some men may need tests that make pictures of the body:

• Bone scan: The doctor injects a small amount of a radioactive substance into a blood vessel. It travels through the bloodstream and collects in the bones. A machine called a scanner detects and measures the radiation. The scanner makes pictures of the bones on a computer screen or on film. The pictures 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 of your pelvis or other parts of the body. 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. The contrast material makes abnormal areas easier to see.
  
  
• MRI: A strong magnet linked to a computer is used to make detailed pictures of areas inside your body. The doctor can view these pictures on a monitor and can print them on film. An MRI can show whether cancer has spread to lymph nodes or other areas. Sometimes contrast material makes abnormal areas show up more clearly on the picture.

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.

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.

Dictionary Terms

A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner.

A dye or other substance that helps show abnormal areas inside the body. It is given by injection into a vein, by enema, or by mouth. Contrast material may be used with x-rays, CT scans, MRI, or other imaging tests.

A series of detailed pictures of areas inside the body taken from different angles. The pictures are created by a computer linked to an x-ray machine. Also called CAT scan, computed tomography scan, computerized axial tomography scan, and computerized tomography.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A procedure in which radio waves and a powerful magnet linked to a computer is used to create detailed pictures of areas inside the body. These pictures can show the difference between normal and diseased tissue. MRI makes better images of organs and soft tissue than other scanning techniques, such as computed tomography (CT) or x-ray. MRI is especially useful for imaging the brain, the spine, the soft tissue of joints, and the inside of bones. Also called magnetic resonance imaging, NMRI, and nuclear magnetic resonance imaging.

The lower part of the abdomen, located between the hip bones.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

Giving off radiation.

A gland that helps produce semen.

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.