When doctors talk about prostate cancer, they use something called the TNM system. The “T” tells you the local extent of the tumor – how big it seems to be within the prostate, whether it has reached the border of the prostate, or whether it has spread locally into the nearby seminal vesicles (tiny organs that sit above the prostate like two wings; picture an apple with two leaves on top). The “N” stands for the presence of any nearby metastases, or bits of cancer that have spread from the original site in the prostate to the lymph nodes, and the “M” is for distant metastases.
When you get a biopsy, the pathologist comes up with the clinical stage. This is the pathologist’s best guess of how much cancer you have, based on how much cancer was found in the biopsy cores, your PSA, MRI or other imaging, and what the Gleason grade of those cells was. If you have surgery to remove the prostate, the doctors will have a lot more to work with – your entire removed prostate and tissue from the nearby lymph nodes. This is called the pathologic stage, and it is definitive.
What are the possibilities here? You could have cancer confined to the prostate, called organ-confined cancer; cancer that has reached the outer wall of the prostate, called capsular penetration; positive surgical margins, which means cancer was found in the cells at the very edge of the surgical specimen (which includes the prostate and some surrounding tissue); invasion of the seminal vesicles; and involvement of the pelvic lymph nodes.
Here’s how that correlates to the TNM system:
Stage What it Means
T1a Cancer not palpable (able to be felt) in a rectal exam, and is found
the prostate); cancer is in 5 percent or less of the removed tissue.
T1b Found incidentally, as in T1a, but greater than 5 percent of the tissue
removed during the TUR is cancerous.
T1c Not palpable; found during needle biopsy due to elevated PSA.
T2a Palpable; involves less than half of one lobe of the prostate.
T2b Palpable; involves more than one half of one lobe, but not both lobes.
T2c Palpable; involves both lobes of the prostate.
T3, T4 Palpable; penetrates the wall of the prostate and/or involves the
N+ Has spread to the lymph nodes.
M+ Has spread to bone.
Terms to know from this article:
A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called a lymph gland.
The removal of cells or tissues for examination under a microscope. When only a sample of tissue is removed, the procedure is called an incisional biopsy or core biopsy. When an entire lump or suspicious area is removed, the procedure is called an excisional biopsy. When a sample of tissue or fluid is removed with a needle, the procedure is called a needle biopsy or fine-needle aspiration.
A doctor who identifies diseases by studying cells and tissues under a microscope.
Gleason Score (GS) - Gleason Grade: A system of grading prostate cancer cells based on how they look under a microscope. Gleason scores range from 2 to 10 and indicate how likely it is that a tumor will spread. A low Gleason score means the cancer cells are similar to normal prostate cells and are less likely to spread; a high Gleason score means the cancer cells are very different from normal and are more likely to spread.
The grade of a tumor depends on how abnormal the cancer cells look under a microscope and how quickly the tumor is likely to grow and spread. Grading systems are different for each type of cancer.
Capable of being felt during a physical examination by a physician; e.g., when the prostate which can be felt during a digital rectal examination.
Not cancerous. Benign tumors do not spread to tissues around them or to other parts of the body.
A mass of excess tissue that results from abnormal cell division. Tumors perform no useful body function. They may be benign (not cancerous) or malignant (cancerous).
prostate-specific antigen (PSA): A substance produced by the prostate that may be found in an increased amount in the blood of men who have prostate cancer, benign prostatic hyperplasia, or infection or inflammation of the prostate.
The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.
see benign prostatic hyperplasia