In order to stage prostate cancer, a staging system is used called the TNM system. The TNM system is used to describe how far the cancer has spread within the prostate gland or body. The TNM system is based on a few key pieces of information including the T category, which is the extent of the primary tumor, the N category, which determines whether the cancer has spread to nearby lymph nodes, the M category, which is determines the absence or presence of distant metastasis, as well as the PSA level and the Gleason score.
One of the most important ways prostate cancer will be staged is by the extent of the primary tumor, which is also known as the T category. There are four subcategories within the T category that describe the local extent of a prostate tumor. These subcategories include T1, T2, T3, and T4.
· T1: The tumor cannot be felt by the Urologist during a digital rectal exam or seen with trans-rectal ultrasound imaging.
o T1a: Cancer is found incidentally during a transurethral resection of the prostate that was done for benign prostatic hyperplasia. Cancer is in no more than 5 percent of the tissue removed.
o T1b: Cancer is found during a TURP but is in more than 5 percent of the tissue removed.
o T1c: Cancer is found by needle biopsy that was done because of an increased PSA.
· T2: The tumor cannot be felt by the Urologist during a digital rectal exam or be seen with trans-rectal ultrasound imaging, but it still appears to be confined to the prostate gland.
o T2a: The cancer is in one half or less of only one side of your prostate.
o T2b: The cancer is in more than half of only one side of your prostate.
o T2c: The cancer is in both sides of your prostate.
· T3: The cancer has grown outside your prostate and may have grown into the seminal vesicles.
o T3a: The cancer extends outside the prostate but not to the seminal vesicles.
o T3b: The cancer has spread to the seminal vesicles.
· T4: The cancer has grown into nearby tissues next to your prostate (other than the seminal vesicles), such as the urethral sphincter, the rectum, the bladder, and/or the wall of the pelvis.