Prostate Cancer — Diagnosis and Staging

There are several important elements of assessing prostate cancer :

Prostate Cancer Diagnosis

When a doctor finds abnormal results during a Digital Rectal Examination (DRE) and/or from a Prostate-Specific Antigen (PSA) test and suspects cancer, the patient will be sent to have a biopsy.

During a biopsy , samples of prostate tissue are taken through a small needle that may be inserted into the rectum or through the perineum into the prostate. An ultrasound probe inserted into the anus guides the needle. The procedure is uncomfortable but is usually not very painful.

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Prostate Cancer Grading

As part of the diagnosis process, prostate cancer is graded and staged. The grade describes how aggressive the cancer is and how fast it is likely to grow.

Most pathologists use the Gleason scale to grade prostate cancer. They look for the most common type of cancer cell in the sample and assign it a number between 1 and 5 — the higher the number, the more abnormal the cells are. Another number is assigned to the second most common type of cell in the sample. The Gleason score is the sum of these two numbers (which will be between 2 and 10).

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Prostate Cancer Staging

Cancer staging is standardized for most types of solid tumors. The Staging System of the American Joint Committee on Cancer (also referred to as the TNM system) is used most often by doctors to describe a patient's cancer. The TNM system involves three scores that describe:

  1. The tumor type
  2. Whether or not lymph nodes are involved
  3. How far the cancer has spread
TNM Staging Guide
T = Tumor
T1: Cannot see tumor without using imaging techniques
T2 - T4: Gradiations of sized and/or extent of the primary cancer
N = Nodes
NO: The cancer has not spread to lymph nodes
N1: Cancer has spread to the lynph nodes
M = Metastasis
MO: No distant metastasis to other organs
M1: Metastasis to other organs

Once the Gleason Score and the TNM categories have been established, this information is combined to determine the cancer’s stage:

  • Stage I: The prostate cancer cannot be detected through a DRE or an imaging machine (MRI, CT scan, etc). Most likely, it was found during a surgical procedure and has a very low Gleason score.
  • Stage II: The prostate cancer has not spread to the lymph nodes or other parts of the body. It was found during a DRE, PSA, needle biopsy , or transrectal ultrasound.
  • Stage III: The prostate cancer has begun to spread beyond the prostate. It may have spread to the seminal vesicles, but it has not spread to the lymph nodes or other parts of the body.
  • Stage IV: The prostate cancer has spread to tissues next to the prostate (other than the seminal vesicles), to lymph nodes, and/or to other, more distant sites in the body.
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