A staging system is a standardized system of indicating the extent to which a cancer has spread. Staging describes the extent or severity of an individual’s cancer based on the size of the original (primary) tumor and the extent to which it has spread within the body. While there are several different staging systems for prostate cancer, the most widely used system in the United States is called the TNM System. It is also known as the Staging System of the American Joint Committee on Cancer (AJCC).1

General Information on Staging

Staging is based on knowledge of the manner in which cancer develops. Cancer cells divide and grow to form a mass of tissue called a tumor. As tumor growth progresses, it can invade nearby organs and tissues. Cancer cells may also break away from the tumor, entering the bloodstream or lymphatic system. By moving through the bloodstream or lymphatic system, cancer can spread from the primary site to form new tumors in other organs. The spread of cancer is called metastasis.2

Purpose of Staging

Staging aids the cancer diagnosis and treatment process in significant ways:

  • Staging helps doctors in effectively planning a patient’s treatment.
  • The stage can be used to estimate a patient’s prognosis (likely outcome or course of the disease).
  • Knowing the stage aids in identifying clinical trials (research studies) that may be suitable for a particular patient.3

Staging helps researchers and health care providers exchange information about patients, providing a common language for diagnosis, treatment and clinical trials.

Tests to Determine Prostate Cancer Stage

The following tests and procedures may be used in the staging process for prostate cancer:

TEST/PROCEDURE EXPLANATION
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.4
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).5
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. 6
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. 7
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 find out if cancer is present.8

The results of these tests are viewed together with the results of the original tumor biopsy to determine the prostate cancer stage.

Staging Prostate Cancer Using the TNM System

The TNM System describes the extent of the primary tumor (T stage), whether the cancer has spread to nearby lymph nodes (N stage), and the absence or presence of distant metastasis (M stage). The TNM System has been accepted by the International Union Against Cancer (IUAC) and the American Joint Committee on Cancer (AJCC).9 The stages described below are based on the most recent version of the AJCC staging manual. The clinical stage is based on your tests before surgery, such as your PSA results and your doctor’s assessment of the cancer from the DRE. If you have surgery, your doctors can determine the pathologic stage, based on the surgery and examination of the removed tissue. There are 4 categories for describing the prostate tumor’s (T) stage, ranging from T1 to T4.10

STAGE EXPLANATION
T1 Your doctor can’t feel the tumor or see it with imaging such as transrectal ultrasound.
T1a The cancer is found incidentally during a transurethral resection (often abbreviated as TURP) for benign prostatic enlargement. Cancer is present in less than 5% of the tissue removed.
T1b The cancer is found after TURP but is present in more than 5% of the tissue removed.
T1c The cancer is found by needle biopsy that was done because of an elevated PSA.
T2 Your doctor can feel the cancer when a digital rectal exam (DRE) is done, but it still appears to be confined to the prostate gland.
T2a The cancer is in one half or less of only one side (left or right) of your prostate.
T2b The cancer is in more than half of only one side (left or right) of your prostate.
T2c The cancer is in both sides of your prostate.
T3 The cancer has begun to spread outside your prostate and may involve the seminal vesicles.
T3a The cancer extends outside the prostate but not to the seminal vesicles.T3b: The cancer has spread to the seminal vesicles.
T4 The cancer has spread to tissues next to your prostate (other than the seminal vesicles), such as your bladder’s sphincter (muscles that help control urination), your rectum, and/or the wall of your pelvis.

Stage Grouping

For many cancers, TNM combinations correspond to one of five stages. Once the T, N, and M categories have been determined, this information is combined, along with the Gleason score, in a process called stage grouping. The overall stage is expressed in Roman numerals from I (the least advanced) to IV (the most advanced).11 This is done to help determine treatment options and the outlook for survival or cure. The following graphic, reproduced courtesy of the National Cancer Institute, shows the urologic organs and prostate cancer stages.12

STAGE I STAGE II
In stage I, cancer is found in the prostate only. It cannot be felt during a digital rectal exam (DRE) and is not visible by imaging. It is usually found accidentally during surgery for other reasons, such as benign prostatic hyperplasia. Stage I prostate cancer may also be called stage A1 prostate cancer.13 In stage II, cancer is more advanced than in stage I, but has not spread outside the prostate. Stage II prostate cancer may also be called stage A2, stage B1, or stage B2 prostate cancer.14
STAGE III STAGE IV
In stage III, cancer has spread beyond the outer layer of the prostate to nearby tissues. Cancer may be found in the seminal vesicles. Stage III prostate cancer may also be called stage C prostate cancer.15 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. Stage IV prostate cancer may also be called stage D1 or stage D2 prostate cancer.16
  1. “Staging: Questions and Answers,” National Cancer Institute. www.cancer.gov. URL:http://www.cancer.gov/cancertopics/factsheet/Detection/staging
  2. Ibid.
  3. Ibid.
  4. “How is Prostate Cancer Staged?,” American Cancer Society, www.cancer.org. URL:http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_prostate_cancer_staged_36.asp
  5. Ibid.
  6. Ibid.
  7. Ibid.
  8. Ibid.
  9. “Staging: Questions and Answers,” National Cancer Institute. www.cancer.gov. URL:http://www.cancer.gov/cancertopics/factsheet/Detection/staging
  10. “How is Prostate Cancer Staged?,” American Cancer Society, www.cancer.org. URL:http://www.cancer.org/docroot/CRI/content/CRI_2_4_3X_How_is_prostate_cancer_staged_36.asp
  11. Ibid.
  12. “Stages of Prostate Cancer,” National Cancer Institute. www.cancer.gov. URL:http://www.cancer.gov/cancertopics/pdq/treatment/prostate/Patient/page2
  13. Ibid.
  14. Ibid.
  15. Ibid.
  16. Ibid.

While clinical studies support the effectiveness of the da Vinci® System when used in minimally invasive surgery, individual results may vary. Surgery with the da Vinci®Surgical System may not be appropriate for every individual. Always ask your doctor about all treatment options, as well as their risks and benefits.

Content provided by Intuitive Surgical. For more information on this topic, please visit www.davincisurgery.com