Cancer staging explains the location of the cancer and whether it has spread to other parts of the body. Once your prostate cancer has been diagnosed and graded with a gleason score, the next step is to know the stage, and specifically if the cancer has spread outside of the prostate. If it has spread, the areas of the body that are impacted also play a role in the type of treatment recommended.

If the gleason score is high enough, additional testing may be needed to see if there are cancer cells outside the prostate. Your doctor will work with you to determine specific factors surrounding your score, but they frequently look for more information if your gleason score is seven or higher. These tests could include one or more of the following:

  • Bone Scan

  • MRI

  • CT Scan

  • Pelvic lymphadenectomy: removal of lymph nodes from the pelvic area to see if the cancer has spread there.

All of the information obtained from these tests, plus your gleason score, will be used to determine the stage of cancer. Knowing the stage of cancer helps your urologist and radiation oncologist identify the best prostate cancer treatment options for you as well as a better understanding of your prognosis.

Types of Prostate Cancer Staging

There are two types of staging for prostate cancer: clinical staging and pathological staging.

  • Clinical staging is determined by the PSA testing, Gleason score, and results of the Digital Rectal Exam (DRE). Once the doctor has all of this information, then you may need additional testing (as mentioned above). The results of these tests can provide more information that your doctor and medical team can then use to identify the stage.

  • Pathological staging is discovered during surgery as well as through laboratory results of biopsies from the tissue removed from the prostate during surgery. This is typically when lymph node involvement is determined.

TNM Staging for Prostate Cancer

The American Joint Committee on Cancer developed a tool called the TNM System that doctors use for staging cancer. Although staging is extremely important for patients to understand, staging continues to evolve, and it is an essential discussion to have with your oncology team. There are five important pieces of information considered when deciding the stage of prostate cancer:

  1. The extent of the main (primary) tumor (T category)

  2. Whether the cancer has spread to nearby lymph nodes (N category)

  3. Whether the cancer has spread (metastasized) to other parts of the body (M category)

  4. The PSA level at the time of diagnosis

  5. The Grade Group. This is determined by examining the tissue samples taken during a prostate biopsy or surgery.

All of this information is then used to create a clear picture of the stage of cancer. These are the stages of prostate cancer:

Stage I: Cancer is considered slow-growing, and the tumor can’t be felt during an exam and involves one-half of one side or less of the prostate. The cancer cells look similar to healthy cells, and the PSA levels are low.

  • T: cT1, cT2a, or pT2
  • N: N0
  • M: M0
  • PSA: Less than 10
  • Grade Group: 1

Stage II: Cancer is found only in the prostate. While the tumor itself is small, it has a higher risk of growing or spreading to other areas of the body. PSA levels are low or medium.

  • Stage IIA: The tumor cannot be felt during the exam and involves half of 1 side of the prostate or less. PSA levels are medium, and the cancer cells look like normal cells, also known as well-differentiated cells. However, this stage may also include large tumors but are only found in the prostate and are still considered well differentiated.

    • T: cT2a, cT2b, or cT2c
    • N: N0
    • M: M0
    • PSA: 10 - 20
    • Grade Group: 1
  • Stage IIB: The cancer remains only in the prostate but is also large enough to be felt during an exam. The PSA level is medium, and the cancer cells are moderately differentiated.

    • T: T1 or T2

    • N: N0

    • M: M0

    • PSA: Less than 20

    • Grade Group: 2 (Gleason score 3+4=7)

  • Stage IIC: The cancer remains only in the prostate and may also be large enough to be felt during an exam. The PSA level is medium, and the cancer cells may be moderately or poorly differentiated.

    • T: T1 or T2

    • N: N0

    • M: M0

    • PSA: Less than 20

    • Grade Group: 3 (Gleason score 4+3=7 or 8)

Stage III: High PSA levels, the tumor shows signs of growth, or the cancer is considered high grade. All of these factors may indicate that the cancer could grow and spread.

  • Stage IIIA: The cancer has spread to nearby tissue and possibly spread to the seminal vesicles. The PSA level tests high.

    • T: T1 or T2

    • N: N0

    • M: M0

    • PSA: At least 20

    • Grade Group: 1 to 4

  • Stage IIIB: The cancer has spread outside of the prostate gland and may have impacted other areas of the body, including the rectum or bladder.

    • T: T3 or T4

    • N: N0

    • M: M0

    • PSA: Any number

    • Grade Group: 1 to 4

  • Stage IIIC: The cancer cells do not look like healthy cells, also known as poorly differentiated.

    • T: Any T

    • N: N1

    • M: M0

    • PSA: Any PSA

    • Grade Group: Any Grade

Stage IV: The cancer has spread beyond the prostate to other areas of the body.

  • Stage IVA: Regional lymph nodes are impacted by the cancer.

    • T: Any T

    • N: N1

    • M: M0

    • PSA: Any PSA

    • Grade Group: Any Grade

  • Stage IVB: Distance lymph nodes, other areas of the body, and the bones have been impacted by the cancer.

    • T: Any T

    • N: Any N

    • M: M1

    • PSA: Any PSA

    • Grade Group: Any Grade

What do the T, N and M Letters and Numbers Mean for Prostate Cancer Staging?

Primary Tumor (T)

  • TX - This means that the main tumor can’t be measured.

  • T0 - The main tumor was not located.

  • T1, T2, T3, and T4 - These categories all refer to the size and extent of the primary tumor. Higher numbers indicate that the tumor has grown more into the surrounding tissues. Additionally, these numbers can be further delineated, such as a T2a or T2b.

Regional Lymph Nodes (N)

  • NX - The cancer in the lymph nodes can’t be measured.

  • N0 - No cancer was located in nearby lymph nodes.

  • N1, N2, N3 - The number after the N refers to how many lymph nodes contain cancer. Higher numbers indicate higher frequency of cancer in lymph nodes.

Distant Metastasis (M)

  • MX - A metastasis can’t be measured.

  • M0 - The cancer has not spread to other areas of the body.

  • M1 - The cancer has spread to other areas of the body.

Your oncologist will have the information needed to be able to determine the stage and then develop a prostate cancer treatment that’s right for you.