What Tests Are Used for Staging Prostate Cancer?

Senior man entering into the MRI Scanner, while mature radiologist is pressing the start button.
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When your cancer is “staged,” your doctor is attempting to formally classify your cancer based on how far it has advanced. This is typically done after you have been diagnosed with prostate cancer following a PSA test or other examination.

The stage of your cancer is one of the most important factors used when determining your overall prognosis and which treatment option is the best for you. For the most part, the lower your stage, the less your cancer has progressed and the better the prognosis.

Virtually all prostate cancer patients undergo some level of staging and it is important to have a basic understanding of how this is accomplished.

Initial Questions and Tests

The first step in staging is accomplished when your physician performs a digital rectal examination (DRE). Nearly all men will undergo at least this level of staging. Often, the physician can feel how large the tumor itself is and whether the tumor is present in one or both halves (or lobes) of the prostate.

The answers you give to questions from your doctor about symptoms, such as bone pain (which may suggest that the cancer has spread to the bones), could also mean a higher stage of cancer is present.

Imaging Tests

  • Bone Scan

    Prostate cancer, when it spreads distantly from the prostate, often invades the bones. Because of this, one of the more common imaging tests used for staging prostate cancer is the bone scan (sometimes called a “radionuclide bone scan”).

    To conduct a bone scan, you will need to have a small amount of radioactive liquid injected into a vein. This material will spread throughout the body, but will preferentially go to sites in the bone where cancer exists.

    A few hours after the material is injected, you will lie on a table while a special camera is used that can detect where the radioactive material has collected. The areas of your body with the most radioactive material will “light up” on the camera.

    Unfortunately, other diseases such as arthritis can also cause damage to the bones and will “light up” on a bone scan. Because of this, if you have areas on your bone scan that concern your physician, you may need more testing of these areas to fully determine whether cancer is present there or not.

  • Computed Tomography Scan (CT Scan or “CAT” Scan)

    A CT scan uses x-rays to make a detailed image of the inside of your body. While you lie on a table, the table will slide in and out of a large ring that produces and detects x-rays. Many x-rays are taken in a short amount of time and then they are combined using computer software to make a set of “slices” showing structures within your body. You may or may not need to have a contrast liquid injected intravenously (I.V., into a vein) in order to achieve a better picture.

    CT scans are helpful in detecting large, bulky tumors in the prostate or elsewhere. They are usually most helpful in determining if large amounts of your cancer have spread to other organs or to lymph nodes near the prostate. They are not particularly good at picking up small clumps of cancer cells throughout the body.

  • Magnetic Resonance Imaging (MRI) Scan

    MRI scans do not use x-rays like CT scans. Instead, they use radio waves to produce a very detailed picture of the body. The images created by an MRI scan are “slices” of the body that can also be combined into a 3D model. You will need to lie on a table that then slides into a large tube for this exam. MRI scans usually take much longer than CT scans to complete and you will be instructed to lie very still throughout the exam. Sometimes, like with CT scans, a liquid contrast material is needed in order to create a better image.

    MRI scans are able to provide more detailed images of soft tissues such as lymph nodes, the prostate, and other nearby structures like the seminal vesicles and bladder.

  • ProstaScint Scan

    The ProstaScint scan is a relatively new development that uses a technique similar to a bone scan. A small amount of radioactive material is injected into your vein. This material, however, is designed to track to places within the body where prostate cancer cells have spread. A special camera is used to create an image of your body with sites of prostate cancer cells. This is especially helpful when trying to determine if soft tissues (not bones) throughout the body have been invaded by prostate cancer cells.

    Invasive Tests

    Sometimes, initial testing and imaging scans are not sufficient to give a proper staging of your cancer. More invasive testing is then needed.

    • Lymph Node Biopsy During Surgery

      When a radical prostatectomy (the most common form of cancer-removing surgery for prostate cancer) is performed, the surgeon is able to remove lymph nodes that are near the prostate. These lymph nodes are some of the earliest places that cancer can spread.

      If the surgeon is highly suspicious that your cancer may have spread (due to very high PSA levels or a high Gleason score), then he or she will remove the lymph nodes during the surgery and have them immediately examined by a pathologist for evidence of cancer. If no cancer is found, the surgery is then completed as planned. If cancer is found in the lymph nodes, however, then usually the surgery is stopped without removing the prostate. This is due to the fact that, if the cancer has already spread outside of the prostate, removal of the prostate adds little benefit to the patient.

    • Lymph Node Biopsy Without Surgery

      Men who choose not to have surgery to remove their prostate (because, for instance, they wish to use radiation therapy instead), in rare circumstances, still need to have their lymph nodes evaluated for the presence of cancer. Both of the following options are only occasionally used.

      • Laparoscopic Biopsy

        For this method, the surgeon does not make any long incisions in the abdomen. Instead, he places small holes in the abdomen through which long, thin instruments (including a tiny camera) are inserted. These instruments can then be manipulated by the surgeon to remove the lymph nodes surrounding the prostate. The lymph nodes are then sent for evaluation.

      • Fine Needle Aspiration (FNA)

        For this method, an interventional radiologist (who is trained specifically to perform procedures such as the FNA), inserts a long needle through the skin and into any enlarged lymph node near the prostate. A tiny sample of the lymph node is then taken out and sent for evaluation.

        Source:

        Trabulsi EJ, Merriam WG, Gomella LG. New imaging techniques in prostate cancer. Curr Urol Rep. 2006 May;7(3):175-80. Review.

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