Cancer Institute A national cancer institute
designated cancer center

Prostate Cancer Staging/Grading

Determining the extent of prostate cancer is important for predicting the course of the disease and in choosing the best treatment. The TNM (tumor, nodes, metastasis) staging system is used to describe a cancer's clinical stage, or how far it has spread.

T categories (clinical)

There are 4 categories for describing the local extent of a prostate tumor, ranging from T1 to T4. Most of these have subcategories as well.

T1:Your doctor can't feel the tumor or see it with imaging such as transrectal ultrasound.

T2: Your doctor can feel the cancer with a digital rectal exam (DRE) or see it with imaging such as transrectal ultrasound, but it still appears to be confined to the prostate gland.

T3:The cancer has begun to grow and spread outside your prostate and may have spread into the seminal vesicles.

T4: The cancer has grown into tissues next to your prostate (other than the seminal vesicles), such as the urethral sphincter (muscle that helps control urination), the rectum, the bladder, and/or the wall of the pelvis.

N categories

N categories describe whether the cancer has spread to nearby (regional) lymph nodes.
NX: Nearby lymph nodes were not assessed.
N0: The cancer has not spread to any nearby lymph nodes.
N1: The cancer has spread to one or more nearby lymph nodes in the pelvis.

M categories

M categories describe whether the cancer has spread to distant parts of the body. The most common sites of prostate cancer spread are to the bones and to distant lymph nodes, although it can also spread to other organs, such as the lungs and liver.
M0: The cancer has not spread past nearby lymph nodes.
M1: The cancer has spread beyond the nearby lymph nodes.

Gleason System

The Gleason grading system is used to help evaluate the prognosis of men with prostate cancer. Together with other parameters, it is incorporated into a strategy of prostate cancer staging which predicts prognosis and helps guide therapy. A Gleason score is given to prostate cancer based upon its microscopic appearance.  Cancers with a higher Gleason score are more aggressive and have a worse prognosis.

Process
The urologist or radiologist performs a prostate needle biopsy, in which a cylindrical sample of prostate tissue is removed through the rectum, using hollow needles, and prepares microscope slides. After a prostate is removed in surgery, a pathologist will slice the prostate for a final examination.

Grades and scores

The pathologist assigns a grade to the most common tumor pattern, and a second grade to the next most common tumor pattern. The two grades are added together to get a Gleason Score.

Traditional Gleason scoring uses a 1-5 scale. However, updated guidelines state that
patterns 1 and 2 should be rarely used if ever, and these numbers are no longer typically assigned in typical prostate needle biopsies. The lowest Gleason grade assigned in clinical practice is 3+3=6.

Research at Stanford has demonstrated that the amount of Gleason pattern 4 in the cancer is indicative of cancer aggressiveness. Therefore a Gleason 3+4=7 cancer is less aggressive than a Gleason 4+3=7 cancer, even though their sum is the same.

Stanford Medicine Resources:

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