Clinical staging

Introduction

All cancers have “staging systems” that physicians use to describe the extent of the cancer or the degree to which it has progressed. These staging systems have changed over the years as we have learned more about cancer.

Your physician may use any one of the following systems to describe the stage of your prostate cancer:

  • The currently recommended system is the TNM system, in which T refers to the primary tumor within the prostate, N refers to the status of the lymph nodes near to the prostate (the pelvic lymph nodes), and M refers to the degree of metastasis — the degree to which prostate cancer has traveled out of the immediate area of the prostate to other organs of the body; the TNM staging system for prostate cancer was last updated early in 2010.
  • The second system still in widespread current use is the American Joint Cancer Commission (AJCC) stage grouping system, which combines clinical staging information from  the TNM system and/or the Jewett-Whitmore system (see below) with information about the histopathological grade of the cancer (the Gleason score).
  • The Jewett-Whitmore system (which is based on the letters ABCD to give the primary stage and numbers and small letters to subdivide them) is an older system that many specialized urologists and urologic oncologists learned in medical school. However, it is almost never used any more today.

This can get very confusing in the beginning, so we have given information about all three of these systems below. After a while, you’ll find that you can get it pretty clear in your head, regardless of which system your doctors are using to talk to you. However, don’t be afraid to ask your doctor if something isn’t clear.


Just click here to watch a brief video presentation
about the various stages of prostate cancer.

We have used the TNM system as our recommended system, because it is now the internationally recognized “normal” system. However, you will find information about the AJCC stage grouping system near the bottom of the page and we have also shown how each of the older Jewett-Whitmore stages corresponds to a specific TNM stage.

 

Stage T1 Disease

Stage T1a disease — Stage T1a disease is always found incidentally, usually in older men who have received a surgical procedure called a transurethral resection of the prostate (TURP) to help them urinate with greater ease because their prostate is enlarged. To qualify as stage T1a, not more than 5 percent of the tissue removed during the transurethral resection can show signs of prostate cancer, and all the cancer cells must be “well differentiated” which means that the cells have a comparatively regular form and order. Stage T1a disease is best compared to stage A1 disease in the older Jewett-Whitmore staging system.

Stage T1b disease — Stage T1b disease is very similar to stage T1a disease. It too is always found incidentally as a result of a transurethral resection of the prostate. However, we call it stage T1b as opposed to stage T1a if more than 5 percent of the tissue removed is prostate cancer tissue or if that tissue is “moderately or poorly differentiated” or both. We say that cancer tissue is moderately or poorly differentiated if the cancer cells have started to become disordered and to lose their structure. Stage T1b is similar to the stage called A2 in the older Jewett-Whitmore system.

Stage T1c disease — We call a prostate cancer stage T1c when it is found at biopsy as a consequence only of the patient having a positive result to a prostate specific antigen (PSA) test but no other clinical sign of the disease (i.e., no abnormality felt on digital rectal examination or visible on any form of imaging test). This stage compares precisely to the so-called stage B0 disease in the Jewett-Whitmore staging system. Because of the rapid increase in the number of patients having PSA tests since the early 1990s, stage T1c has become an extremely common stage of prostate cancer to be diagnosed.

Stage T2 Disease

Stage T2a disease — When a physician says a patient has stage T2a disease, it means the physician can feel the tumor in not more than half of one side (one lobe) of the prostate when he does a physical examination with his finger (a digital rectal examination or DRE). The physician calls this a “palpable” tumor. Stage 2a disease may also be identified when the physician can clearly see what appears to be a tumor in not more than one half of one lobe of the prostate as a result of some type of imaging test (e.g., an ultrasound or an MRI image). Stage T2a disease is very similar to stage B1 disease in the Jewett-Whitmore system of staging.

Stage T2b disease — Like stage T2a disease, stage T2b disease is also something the physician can feel when he does a digital rectal examination. In this case, however, more than half of one lobe (but not both lobes) of the prostate must have palpable tumor which the doctor can feel. Stage T2b disease may also be identified when the physician can clearly see what appears to be a tumor or tumors in both halves of one lobe of the prostate as a result of some type of imaging test (e.g., an ultrasound or an MRI image). Again, stage T2b disease is very like stage B2 disease in the older Jewett-Whitmore system.

Stage T2c disease — Stage T2c disease is similar to the other two stage T2 disease described above, except that in this stage the doctor is able to feel palpable tumor in both sides or lobes of the prostate, the left side and the right side or see such a tumor or tumors using an imaging test.

Stage T3 Disease

The two forms of stage T3 disease require extension of prostate cancer tissue through the so-called “prostatic capsule” and out of the prostate into the immediately surrounding tissue.

Stage T3a disease — In the case of stage T3a disease the prostate cancer tissue may have extended outside the prostate capsule on one side (unilateral) or both sides (bilateral) of the prostate. Thus stage T3a is very similar to stage C1 in the Jewett-Whitmore system

Stage T3b disease — Stage T3b disease is used to describe prostate cancer which has extended into one or both of the seminal vesicles (which is roughly comparable to the older stage C2 disease). However, stage T3b is also used to define disease which combines extracapsular extension with either unilateral or bilateral seminal vesicle involvement (which is comparable to stage C3 in the Jewett-Whitmore system).

Note: An older form of the TNM staging system included a stage known as stage T3c disease that was eliminated in more recent updates to this staging system.

Stage T4 Disease

Stage T4 is a stage of prostate cancer which had no true equivalent in the Jewett-Whitmore system. Tumor is still localized to the pelvic region, but has definitely escaped from the prostate and seminal vesicles. Tumor is normally either fixed to or invades surrounding areas, such as the bladder neck, the external sphincter, the rectum, the levator muscles, and/or the pelvic wall.

Regional Lymph Node Staging

The regional lymph nodes are the lymph nodes within the true pelvic area. They do not include distant lymph node that are outside the pelvic area.

Stage Nx disease — If the patient’s cancer is classified as Nx, this means that we simply do not know the status of the regional lymph nodes because they have not been assessed.

Stage N0 disease — If the patient’s cancer is classified as N0, then the lymph nodes have been assessed and there is no sign whatsoever of any cancer in the nodes examined.

Stage N1 disease — Cancer classified as N1 means that there is definitely cancer in one or more regional lymph nodes.

Metastatic Staging

Metastatic staging refers to the presence of prostate cancer outside the pelvic area (most commonly as distant foci of cancer known as metastases).

Stage Mx disease — If the patient’s cancer is classified as Mx, this means that the patient has not received tests that would allow any assessment of the possibility of metastasis.

Stage M0 disease — If the patient’s cancer is classified as M0, then the patient has been assessed in one or more ways and there is no evident sign whatsoever of any cancer outside the pelvic area. Many men with stage M0 disease may still have strong evidence of invisible micrometastatic disease because their PSA is rising after (for example) surgery and radiation therapy. Such men would be classified as having stage D1 disease according to the Jewett-Whitmore staging system.

Stage M1 disease — If the patient’s cancer is classified as M1, then there is clear evidence of prostate cancer somwhere outside the pelvic area. This stage is exactly comparable to stage D2 of the Jewett-Whitmore system. Some physicians may also use the following subclassifications to denote the extent of the metastatic disease:

  • Stage M1a: Metastasis is evident in one or more non-regional lymph node(s)
  • Stage M1b: Metastasis is evident in a bone or bones (e.g., in the hip or the spine)
  • Stage M1c: Metastasis is evident in other site(s), such as the lung or liver, with or without the presence of bone disease

Castration-Resistant or Hormone-Refractory Disease

In the old Jewett-Whitmore staging system, physicians often used the term stage D3 to refer to patients whose prostate cancer was no longer responding to hormonal therapies. There is no equivalent to this stage in the new TNM system.

The AJCC Stage Grouping System

The AJCC stage grouping system groups men with prostate cancer into four basic stage categories:

  • Stage I — men with very early stage, low grade disease
  • Stage II — men with early stage disease but higher grade (and therefore potentially more aggressive) disease
  • Stage III — men with cancer that has clearly started to escape from the prostate (and is therefore locally advanced)
  • Stage IV — men with advanced disease who have either high probability of (invisible) micrometastasis or clearly metastatic disease

If you click here (or on the image of the table immediately below), you will open a new window where you can easily see the whole table. You will be able to understand from this table exactly how each TNM stage or Jewett-Whitmore stage “fits” into one of the four AJCC stage groups.

 

Staging Systems in Clinical Practice: A Case Example

Mr Johnston is referred to a urologist by his primary care physician following a preliminary examination. Mr Johnston is 69 years old. He hasn’t seen a doctor in years, because until recently he has considered himself to be in very good health for his age. However, he has been getting a very mild pain in his spine and lower back, is tiring rather more easily than he did a year ago, and has a PSA of 11.1 ng/ml. The digital rectal examination (DRE) indicates a clearly palpable abnormality on the right lobe of Mr Johnston’s prostate.

The urologist repeats the PSA test and the DRE. He can also feel a hard abnormality on the right lobe of Mr. Johnston’s prostate. Subject to the result of the repeat PSA, the urologist advises Mr Johnston that he may have T2aNxMx or T2bNxMx prostate cancer. T2a and T2b both mean that a probable tumor is evident on one side or lobe of the prostate in a digital rectal exam. Nx means that no information is yet available on the status of Mr Johnston’s lymph nodes. Mx means that there is no information yet available on Mr. Johnston’s risk for metastatic disease. However, Mr Johnston is showing clear and classic signs of metastatic prostate cancer through the combination of spinal bone pain and tiredness, although his PSA level appears to be low for someone at risk for metastatic disease.

The physician states that he would want to carry out additional tests before confirming this diagnosis for Mr Johnston, starting with a TRUS-guided prostate biopsy and a bone scan.

Content of this page last reviewed and updated October 2, 2014
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