Once prostate cancer has been found, more tests will be done to determine the level of malignancy (the grade of the cancer) and to find out if the cancer has spread (or metastasized) from the prostate to other parts of the body (the staging of the cancer). To plan treatment, a doctor needs to know (1) whether the cancer has spread, as well as (2) the grade and (3) the stage of the disease. The following grades and stages are used for prostate cancer.

1. Determining Whether the Cancer has Metastasized (Staging)

   There are several tests that can help determine whether the cancer has spread beyond the prostate to other parts of the body, including:

   Bone Scan

   A bone scan may show areas of rapid bone growth that can be associated with cancer. Prostate cancer, when it spreads to the skeleton, typically has a classic pattern of random and variable hot spots that show up on the scan. These patterns frequently occur along the spine, ribs and skull. The lack of these patterns does not, however, rule out the spread of the cancer. If the patterns are not visible on the scan, it may only mean that there are no cancer spots in the skeleton large enough to be detected by the equipment.

   CT Scan (also called CAT Scan)

   A CT scan (or CAT scan), which stands for computerized axial tomography, uses computerized X-ray pictures to evaluate internal organs of the body. The CT scan is most often used prior to administering radiation therapy (discussed further under cancer treatment) in order to help calculate how much radiation and where exactly in the body the radiation should be delivered.

2. Grading of the Prostate Cancer

   The malignancy (or aggressiveness) of the prostate cancer is documented by assigning a grade to the cancer based upon the appearance of the cancer cells and how they are arranged together. The Gleason scale is a standard grading system which assigns cancer cells a score from 1 to 10. These scores are broken down into three main levels:

   • low-grade cancer: have a Gleason score of not more than 4. This is the least-aggressive type of cancer. Cells from low-grade prostate cancer have an appearance most like normal cells, and tend to be slow-growing. Such cancer cells are called well-differentiated.
   • intermediate-grade cancer: have a Gleason score between 4 and 7. By the time the cancer has become intermediate-grade, it has turned more aggressive than a low-grade cancer. Intermediate-grade cancer cells have an appearance that is less like normal cells and is often faster growing than low-grade cancer cells. Such cells are called moderately-differentiated.
   • high-grade level: have a Gleason score between 8 and 10. This is the most aggressive type of cancer. Cells from high-grade prostate cancer are the least like normal prostate cells. They are rapid-growing and highly aggressive, often spreading into the lymph nodes and bone. Such cells are called poorly-differentiated.

   The higher the grade of the cancer, the more difficult it is to successfully treat the cancer. The risk of dying from prostate cancer increases substantially for men who are diagnosed with high-grade (or poorly-differentiated) prostate cancer.

3. Staging of the Prostate Cancer

   The following stages are used for prostate cancer.

   Stage T1 (Stages A and B)

   The tumor is located only within the prostate and has not spread to other parts of the body. At this stage, prostate cancer does not cause any symptoms. The tumor is too small to be felt during a DRE and cannot be seen on an imaging scan. These tumors will most likely only be found during follow-up of screening tests showing abnormal PSA levels.

   • Stage T1a (A1): The tumor is incidentally found to be in 5% or less of a prostate tissue sample.
   • Stage T1b (A2): The tumor is incidentally found to be in more than 5% of a prostate tissue sample.
   • Stage T1c (B0): The tumor is identified by a needle biopsy as a follow-up of screening tests showing an elevated PSA result.

   Stage T2 (Stage B)

   The tumor is STILL located only within the prostate and has not yet spread to other parts of the body, but is now large enough to be felt during a DRE. Men who have Stage T2 often do not experience any symptoms.

   • Stage T2a: The tumor involves less than half of one lobe of the prostate. The tumor can usually be felt and is often discovered during a DRE exam.
   • Stage T2b (B1): The tumor involves more than half of one lobe of the prostate and can usually be felt during a DRE exam.
   • Stage T2c (B2): The tumor involves both lobes (the left and the right) of the prostate and is felt during a DRE exam.

   Stage T3 (Stage C)

   The tumor has spread to outside of the prostate into immediately surrounding tissue, possibly including the seminal vesicles.

   • Stage T3a (C1): The tumor has spread to outside of the prostate on only one side.
   • Stage T3b (C2): The tumor has spread to outside of the prostate on both sides.
   • Stage T3c (C3): The tumor has spread to one or both of the seminal tubes.

   Stage T4 (No equivalent in A, B, C, D system)

   The tumor is still within the pelvic region but may have spread to other areas.

   • Stage T4a: The tumor has spread beyond the prostate to any or all of the bladder neck, the external sphincter, and/or the rectum.
   • Stage T4b: The tumor has spread beyond the prostate and now may affect the levator muscles (the muscles that help to raise and lower the organ) and/or the tumor may be attached to the pelvic wall.

   N Staging (Stage D)

   • Stage N0: No metastasis to regional lymph nodes.
   • Stage N1: (Stage D1) Prostate cancer cells have metastasized (spread) to a single lymph node in the pelvic area and are 2 cm (approximately 3/4 of one inch) or less in size.
   • Stage N2: (stage D1) Prostate cancer cells have metastasized (spread) either to a single lymph node and are more than 2 cm but less than 5 cm (approximately 2 inches) in size, or the prostate cancer cells are found in more than one lymph node and are no larger than 5 cm in size.
   • Stage N3: Prostate cancer cells have metastasized to the lymph nodes and are larger than 5 cm in size.

   M Staging (Stage D)

   • Stage M0: No distant metastasized.
   • Stage M1: (Stage D2) The prostate cancer cells have metastasized (spread) beyond the pelvic area to other parts of the body, which can include the spinal column. Bone pain, weight loss, and tiredness are common symptoms.

Once the diagnosis and workup are completed, a proper treatment plan can be developed.