What do the different stages of prostate cancer mean?

One in 7 men will be diagnosed with prostate cancer in their lifetime.  This means, you or someone you know will be diagnosed with prostate cancer at some point during your life.  Many people can find it confusing to sift through all the information out there, or perhaps don’t know where to start. Here is a guide to the different stages of prostate cancer and what they mean.  Hopefully this will help those looking for clearer information learn more about prostate cancer.

 There are two different types of prostate cancer staging: clinical and pathologic.  Clinical stage refers to the approximation of cancer at diagnosis and is based on digital rectal exam (DRE), lab tests, biopsy and imaging.  Pathologic stage, on the other hand, refers to staging after the prostate has been removed and, as such, is considered more accurate than clinical stage.  This is just one advantage of undergoing prostatectomy (surgical removal of the prostate) compared to other modalities.

The most common staging system for prostate cancer is the American Joint Committee on Cancer (AJCC) TNM system.  It is based on five critical aspects: 1- extent of primary tumor (T), 2- has the cancer spread to lymph nodes (N), 3- absence or presence of distance metastasis (M), 4- PSA at diagnosis and 5- Gleason score.

Clinical stages of prostate cancer include:

T1: A tumor that is neither palpable via DRE nor visible via imaging

T1a: Tumor is found incidentally in ≤5% of tissue (i.e. after a transurethral resection of the prostate [TURP])

T1b: Tumor is found incidentally in >5% of tissue

T1c: Tumor identified by needle biopsy done because of increased PSA

T2: Tumor is confined to the prostate and is palpable via DRE and/or visible via imaging

T2a: Tumor involves ≤ ½ of one (left or right) lobe

T2b: Tumor involves more than ½ of one lobe, but not both lobes

T2c: Tumor involves both lobes

T3: Tumor has spread beyond prostate capsule

T3a: Tumor extends outside the prostate but not into seminal vesicles

T3b: Tumor invades the seminal vesicle(s)

T4: Tumor invades adjacent structures (other than seminal vesicles) including bladder, urethral sphincter, rectum and/or pelvic wall

Pathologic stages of prostate cancer include:

pT2: Tumor confined to prostate

pT2a: Tumor involves ½ of lobe or less

pT2b: Tumor involves more than ½ of one lobe, but not both lobes

pT2c: Tumor involves both lobes

pT3: Tumor extends beyond prostate capsule

pT3a: Extraprostatic extension or microscopic invasion of bladder neck

pT3b: Tumor invades the seminal vesicle(s)

pT4: Tumor invades rectum, levator muscles and/or pelvic wall

N: Lymph node involvement:

Nx: Adjacent lymph nodes were not assessed

N0: Cancer has not spread to adjacent lymph nodes

N1: Cancer has spread to one or more pelvic lymph nodes

M: Metastases (presence or absence):

M0: Cancer has not spread past adjacent lymph nodes

M1: Cancer has spread beyond pelvic lymph nodes

M1a: Cancer has spread to distant lymph nodes (outside the pelvis)

M1b: Cancer has spread to bones

M1c: Cancer has spread to other organs (i.e. lungs, liver, brain)