Prostate Cancer Grading & Staging

If your biopsy shows the presence of prostate cancer, the pathologist, a doctor who identifies diseases by studying tissues under a microscope, assigns each tissue sample a grade. The grade indicates how far the cells have traveled along the path from normal to abnormal.

The grade offers a good clue to your tumor's behavior: a tumor with a low grade is likely to be slow-growing; a tumor with a high grade is more likely to grow aggressively or already to have spread outside the prostate, called metastasized. The most widely used grading method for prostate cancer is known as the Gleason grading system.

One way of grading prostate cancer, called the Gleason system, uses scores of 2 to 10. Another system uses G1 through G4. In both systems, the higher the score, the higher the grade of the tumor. High-grade tumors generally grow more quickly and are more likely to spread than low-grade tumors.

Gleason Scores
The Gleason grading system assigns a grade to each of the two largest areas of cancer in the tissue samples. Grades range from 1 to 5, with 1 being the least aggressive and 5 the most aggressive. Grade 3 tumors, for example, seldom have metastases, but metastases are common with grade 4 or grade 5. Metastases is when the cancer has spread to other parts of the body.

The two grades are then added together to produce a Gleason score . A score of 2 to 4 is considered low grade; 5 through 7, intermediate grade; and 8 through 10, high grade. A tumor with a low Gleason score typically grows slowly enough that it may not pose a significant threat to the patient in his lifetime.

Gleason Scores
The Gleason grading system assigns a grade to each of the two largest areas of cancer in the tissue samples. Grades range from 1 to 5, with 1 being the least aggressive and 5 the most aggressive. Grade 3 tumors, for example, seldom have metastases, but metastases are common with grade 4 or grade 5. Metastases is when the cancer has spread to other parts of the body.

The two grades are then added together to produce a Gleason score . A score of 2 to 4 is considered low grade; 5 through 7, intermediate grade; and 8 through 10, high grade. A tumor with a low Gleason score typically grows slowly enough that it may not pose a significant threat to the patient in his lifetime.

What is staging of prostate cancer?
Once your cancer has been identified, the doctor wants to know how large it is and how far it has spread. Depending on its size and spread, your doctor will stage your tumor. Information on your tumor stage, along with tumor grade and PSA level, is central to choosing your treatment and to monitoring its success.

Stage refers to how far the cancer has spread in the prostate or to other areas of the body. Early prostate cancer (ages I and II) is localized or restricted to the area where the cancer started. There is no sign of the cancer spreading.

Stage III prostate cancer, means the cancer has spread beyond the outer layer of the prostate to nearby tissues and may be found in the seminal vesicles, the glands that help produce semen. It is also called stage C prostate cancer.

Stage IV prostate cancer means the cancer has spread to lymph nodes and/or to other tissues or organs. Lymph nodes are rounded masses of lymphatic tissue that are surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store white blood cells or lymphocytes. Lymphatic fluid is the clear fluid that travels through the lymphatic system. It carries cells that help fight infections and other diseases.

Tumor stages are:

• Localized
  • Stage I or A or T1: a tumor that cannot be felt, called nonpalpable.
  • Stage II or B or T2: a tumor that can be felt, called palpable, but is confined to the prostate gland.
• Regional
  • Stage III or C or T3: a tumor that has grown through the prostate capsule, perhaps into the seminal vesicles, a gland that helps produce semen.
  • T4: a tumor that has grown into nearby muscles and organs.
• Metastatic
  • Stage IV or D and N+ or M+: tumors that have metastasized, spread, to the regional, pelvic lymph nodes (N+) or more distant parts of the body (M+).

Staging Systems
One of two widely used staging systems, known as TNM, evaluates Tumor size and spread, cancer in the nearby lymph nodes, and whether the cancer has established distant metastases. Metastases are tumors formed from cells that have spread from the primary, or original tumor. The second system measures the same tumor characteristics, but uses an ABCD rating.

What tests are used for staging prostate cancer?
The main tests used for clinical staging of prostate cancer are a Digital Rectal Exam (DRE), prostate specific antigen (PSA), and transrectal ultrasound (TRUS). Extensive information can be found about DRE and PSA under the Testing for Prostate Cancer section.

TRUS uses an ultrasound probe inserted in the rectum to visualize the area on a screen. Bone scans may be used when distant metastases are suspected. A bone scan is a technique that creates images of bones on a computer screen or on film. During a bone scan, a small amount of radioactive material is injected into a blood vessel and travels through the bloodstream where it collects in the bones and is detected by a scanner. Metastases are tumors formed from cells that have spread from the primary, or original, tumor.

When clinical staging suggests that cancer has spread to the lymph nodes or beyond, bone scans can be used to look for metastases to bone, a common site of prostate cancer spread. However, research now shows that patients with PSA levels of 10 ng/ml or less, without bone pain, are so unlikely to have bone metastases-regardless of tumor stage or grade-that doctors often recommend that these patients can skip the bone scan.

What is primary cancer?
Cancer can begin in any organ or tissue of the body. The original tumor is called the primary cancer or primary tumor. It is usually named for the part of the body or the type of cell in which it begins.

What is metastasis, and how does it happen?
Metastasis means the spread of cancer. Cancer cells can break away from a primary, or original, tumor and enter the bloodstream or lymphatic system, the system that produces, stores, and carries the cells that fight infections. That is how cancer cells spread to other parts of the body.

When cancer cells spread and form a new tumor in a different organ, the new tumor is a metastatic tumor. The cells in the metastatic tumor come from the original tumor. This means, for example, that if breast cancer spreads to the lungs, the metastatic tumor in the lung is made up of cancerous breast cells, not lung cells. In this case, the disease in the lungs is metastatic breast cancer, not lung cancer. Under a microscope, metastatic breast cancer cells generally look the same as the cancer cells in the breast.

Normal cells that have been stained in order to view

What questions should I ask my physician?
No written information can take the place of talking directly with your health care professionals. If you don't understand the answers to your questions, ask him or his staff to explain further.

Many men find it helpful to write down their questions ahead of time. Below are some of the most common questions. You may have others. Jot them down as you think of them, and take the list with you when you see your physician.

• Could my symptoms be a sign of cancer?
• What tests do you recommend? Why?
• If I don't have cancer, what can I do about my symptoms?
• If I do have cancer, what stage is it? What grade? What is my PSA level?
• Would it be useful to get a second opinion from a second pathologist?
• What is my prognosis? Is recurrence likely?
• Do I need additional tests to look for lymph node involvement or metastases?
• What are my treatment options? What are the benefits?
• What are the possible side effects? How can they be managed?
• Are there clinical trials that would be appropriate for me?
• How much experience does your physician have? How many times a year does your physician perform this procedure?