Prostate Cancer Staging

The stage is one of the most important factors in selecting treatment options. It is also the most significant (but not the only) factor in predicting a man's outlook for survival (prognosis). A prostate cancer's stage indicates how far it has spread within the prostate, to nearby tissues, and to other organs.

An overview of the stages of prostate cancer:

Stage I: The cancer cannot be found during a digital rectal exam. It is found as a result of prostate biopsies for an elevated or increasing PSA or by chance when surgery is done for another reason, usually for lower urinary tract symptoms. (Stage I=T1)

Stage II: The cancer is palpable — a nodule is detected on prostate exam, but it has not spread outside the prostate. (Stage II=T2)

Stage III: The cancer has spread outside the prostate. It may be in the tissues adjacent to the prostate or invaded the seminal vesicles. It has not spread to the lymph nodes. (Stage III=T3)

Stage IV: The cancer may be in nearby pelvic muscles or organs (beyond the seminal vesicles). It may have spread to the lymph nodes. It may have spread to other parts of the body. (Stage IV includes T4 and spread to the pelvic lymph nodes or distant sites)

A staging system is a standardized way in which the cancer care team describes the extent to which a cancer has spread. The TNM System of the American Joint Committee on Cancer (AJCC) is the most commonly used system in the United States. The TNM System describes the extent of the primary tumor (T), the absence or presence of spread to the nearby lymph nodes (N), and the absence or presence of spread to distant organs (M). The spread of cancer is called metastasis.

 
Although in this AJCC staging system, the T, N, M stages are combined into a single Roman numeral (I-IV), often it is not needed for prostate cancer because the AJCC stages follow the T stage. Stage I=T1, Stage II=T2, Stage III=T3, and Stage IV includes T4 and spread to the lymph nodes (N1)  or distant sites (M1).

A detailed look at the TNM System of Cancer stages:

T CATEGORIES There are two types of T classifications for prostate cancer:

  • The clinical stage is your doctor's best estimate of the extent of the disease based on digital rectal exam (DRE), needle biopsy, and any imaging studies that were done.
  • The pathologic stage is based on surgical removal and examination of the entire prostate gland, both seminal vesicles (two small sacs next to the prostate that store semen) and, in some cases, nearby lymph nodes.

The clinical stage is used in making treatment decisions. However, the clinical stage may underestimate the amount of cancer and the presence of metastasis (spread of the cancer). If surgery is done, the pathologic stage assigned after surgery is more accurate. Men who do not have a radical prostatectomy (surgery to remove the prostate gland, seminal vesicles, and nearby tissues) do not have a pathologic T stage determined. There are 4 categories for describing the prostate cancer's T stage.

TX is the primary tumor cannot be assessed.

T0 is there is no evidence of primary tumor. 

T1 refers to a tumor that is not felt during a digital rectal exam, but cancer cells are found in a prostate biopsy or prostactectomy specimen. T1 prostate cancers can be further subclassified as T1a, T1b and T1c.

  • T1a describes prostate cancers found by accident during transurethral resection of the prostate (TURP) (a procedure in which an instrument is inserted through the urethra to remove prostate tissue that is pressing against the upper part of the urethra and restricting the flow of urine) or open prostate removal (simple prostatectomy). When prostate tissue is removed during these surgical procedures and checked under the microscope, cancer may be found, even though the doctor did not expect cancer to be present. T1a indicates that less than 5% of the tissue removed is cancer and more than 95% is benign.
  • T1b also describes cancers found incidentally during TURP or simple prostatectomy, but more than 5% of the removed tissue is cancer.
  • T1c cancers are found by biopsy. In these cases a core needle biopsy is usually done because the PSA blood test result was elevated, suggesting that a cancer might be present.

T2 means that a doctor can feel the prostate cancer by DRE and that the cancer is thought to remain within the prostate gland. This category is subclassified into T2a and T2b and T2c.

  • T2a means that the cancer is in only one side of the prostate, and is in only half (or less) of that side.
  • T2b cancers are in only one side of the prostate, but are in more than half of that side.
  • T2c cancers are found in both sides of the prostate.

T3 means the cancer has spread beyond the outer rim (capsule) of the prostate into the connective tissue next to the prostate and/or the seminal vesicles and/or the bladder neck. Cancer has not spread to any other organs. This group is subdivided into T3a and T3b.

  • In T3a, the cancer is growing outside the prostate but has not spread to the seminal vesicles.
  • A T3b cancer has spread to the seminal vesicles.

T4 means that the cancer has spread to tissues next to the prostate (other than the seminal vesicles or bladder neck), such as the external sphincter (muscle that helps control urination), the rectum, the muscles in the pelvis, or the wall of the pelvis.

N Categories

The N category is determined by whether or not the cancer has been found in nearby lymph nodes.

  • NX means that tests to detect lymph node spread have not been done.
  • N0 means that the cancer has not spread to any lymph nodes.
  • N1 means spread to nearby lymph nodes in the pelvis.

M Categories

The M category stands for metastasis (whether or not the cancer has spread to distant organs).

  • M0 means that the spread of cancer cannot be found by physical exam or x-rays but is presumed present due to abnormal PSA blood tests.
  • M1 means the cancer has spread to distant sites.
  • M1a – the cancer has spread to distant lymph nodes.
  • M1b – the cancer has spread to bone(s).
  • M1c – the cancer has spread to other organs such as lungs, liver or brain.

Recurrent cancer is cancer that has come back (recurred) after a time when it was in remission (could not be detected). It may recur in or near the prostate, or in any other part of the body, such as the bones. Read more information on recurrent cancer.