Prostate Cancer 911

Staging and Survival Rates

Staging is a method of describing where the cancer is located, where it has spread, and whether it is affecting other parts of the body.

Prostate cancer staging is based on a number of different factors, including prostate cancer screening tests, such as the digital rectal exam (DRE) and the prostate-specific antigen (PSA) test.

Doctors use diagnostic tests to determine cancer’s stage. Staging may not be complete until these tests are finalized. Knowing the correct stage helps the doctor decide the best course of treatment and the possible outcomes.

There are 2 types of staging for prostate cancer:

The Clinical Stage – The clinical stage is based on the results of tests that can be done prior to the surgery. They include the DRE, biopsy, X-rays, CT and/or MRI scans and bone scans. X-rays, bone scans, CT scans and MRI scans may not always be needed. They are recommended based on the PSA level, the size of the cancer, which is determined by its grade and volume and the clinical stage of the cancer.

The Pathologic Stage – The pathologic stage is based on information found during surgery, plus the laboratory results referred to as pathology, of the prostate tissue removed during surgery. The surgery often includes the removal of the entire prostate and some lymph nodes.One important part of the staging process is determining the grade of the cancer. The grading system is based on the microanalysis of the prostatic tissue. While the stage of the cancer is determined based on the macro appearance of the tumor, in connection with the nearby organs and tissues, the grade of cancer is usually determined after a biopsy, when the cells are analyzed under a microscope.

Prostate cancer grading systems

Gleason Score

In the 1960s, Dr. Donald Gleason developed a prostate cancer grading system, called the Gleason Score. Dr. Gleason noticed that normal prostate cells go through 5 distinctive patterns until they transform into tumor cells. Based on this differentiation, prostate cells are scaled from 1 to 5. Grade 1 cells have the same appearance as the normal cells, while grade 5 cells are tumor mutations that cease to resemble the normal cells. Gleason grade can vary from 1 to 5, grade 1 cells are considered low-grade and grade 5 cells are considered high-grade. The Gleason Score is calculated based on the Gleason Grade.

The pathologist who examines the biopsy sample will identify 2 important cells patterns and will determine

  1. The Gleason Grade of the predominant pattern – the largest area of the tumor
  2. The Gleason Grade of the second predominant pattern – the cells of the next largest area of the tumor

The 2 grades that were assigned will then be added together and result in the Gleason Score. The Gleason Score can vary from 2-10, but usually, pathologists assign scores between 6-10, 6 being the lowest cancer score.

How to understand the Gleason Score

For instance, if the Gleason Score is written 4+3=7, this means 4 is the grade assigned to the most cancerous cells, while 3 is the grade of the next largest section of the tumor. Together they make up the total Gleason Score, in this instance 7.

A Gleason Score of 6 is considered low-grade. It describes cancer cells that resemble the normal cells and, therefore, the cancer is slow-growing.

A Gleason Score of 7 is considered an intermediate grade, with a medium risk of aggressive cancer. In this case, it is very important to know what is the primary grade (of the largest area). If the primary grade is 3 and the secondary grade is 4, the cancer is not that likely to spread so quickly or cause important problems while a Gleason Score of 7, with the primary grade of 4 and the secondary grade of 3 is more likely to be more aggressive and high-risk.

Consider asking about your primary Gleason Grade, especially when your Gleason Score is 7 and the Gleason Grades are not specified.

A Gleason score of 8-10 is considered to be high-risk. Cancers are likely to spread more quickly and be more aggressive.

For a better understanding of your particular situation, do not hesitate to contact a urologist!

 

ISUP Grade Group

The ISUP Grade Group is a simpler grading system, released in 2014 by the International Society of Urological Pathologists. The ISUP Grade Group is formed by just 5 grades, ranging from 1-5, based on the Gleason Score Value.

  • ISUP Grade Group 1 -It is considered a low-risk group, with a Gleason Score of less or equal to 6.
  • ISUP Grade Group 2 -It is considered an intermediate-favorable risk group, with a Gleason Score of 7, with the primary grade of 3 and the secondary grade of 4.
  • ISUP Grade Group 3 -It is considered an intermediate-unfavorable risk group, with a Gleason Score of 7, with the primary grade of 4 and the secondary grade of 3.
  • ISUP Grade Group 4 -It is considered a high-risk group, with a Gleason Score of 8.
  • ISUP Grade Group 5 -It is considered a high-risk group, with a Gleason Score of 9-10.

There are hospitals that report both the Gleason Score and the ISUP Grade Group, so it is very important to know the significance of both values.

TNM Staging System

In order to determine the stage of a patient’s prostate cancer, most doctors start by using the TNM staging system, which helps describe different aspects of cancer’s growth and spread. The TNM staging system stands for tumor, node, and metastasis:

Tumor (T) – What is the size of the original tumor? Has it invaded the nearby tissues?

  • Tx – Primary tumor can not be assessed
  • T0 – No evidence of primary tumor
  • T1 – The tumor is not palpable or visible during imaging exams
  • T1a – The tumor was incidentally found during a TURP and is less than 5% of tissue resected
  • T1b – The tumor was incidentally found during a TURP and is more than 5% of tissue resected
  • T1c – The tumor was identified after a biopsy
  • T2 – The tumor is organ-confined
  • T2a – The tumor covers one half or less than one half of one lobe of the prostate
  • T2b – The tumor covers more than one half of one lobe of the prostate
  • T2c – The tumor covers both lobes of the prostate
  • T3 – The tumor extends through the prostatic capsule
  • T3a – The tumor extends unilateral or bilateral
  • T3b – The tumor invades the seminal vesicles
  • T4 – The tumor invades other structures ( the bladder or the pelvic floor)

Node (N) – Has the tumor spread to the lymph nodes? If so, where and how many lymph nodes are involved?

  • NX – Regional lymph nodes were not assessed
  • N0 – No metastasis in the regional lymph nodes
  • N1 – Regional lymph nodes metastasis

Metastasis (M) – Has cancer metastasized (spread) to other parts of the body? If so, where and how much?

  • M0 – No distant metastasis
  • M1 – Distant metastasis

What are the stages of prostate cancer?

Stage 1 Prostate Cancer

In stage 1, the cancer is confined to the prostate. Stage 1 prostate cancer can’t be detected during a digital rectal exam (DRE) and is usually expected to be slow-growing. The tumor is one half of one lobe of the prostate or even less (T1/T2a). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). The PSA level is below 10ng/ml. The Grade Group is 1.

Stage 2 Prostate Cancer

In stage 2, cancer can be detected during a digital rectal exam (DRE). It’s still confined to the prostate, but the cells may be more abnormal and may grow faster.

  • Stage IIA – The tumor may involve more than one half of one lobe or even both lobes of the prostate but it is still organ-confined (T2b-c). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). The PSA level is 10-20 ng/ml. The Grade Group is 1.
  • Stage IIB – The tumor may involve both lobes of the prostate or less than that (T1-2). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). The PSA level is below 20 ng/ml. The Grade Group is 2.
  • Stage IIC – The tumor may involve both lobes of the prostate or less than that (T1-2). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). The PSA level is below 20 ng/ml. The Grade Group is 3-4.
     
     

Stage 3 Prostate Cancer

In stage 3, cancer has now spread beyond the prostate and may have potentially spread into the nearby seminal vesicles.

  • Stage IIIA – The tumor may involve both lobes of the prostate or less than that (T1-2). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). The PSA level is below or equal to 20 ng/ml. The Grade Group is 1-4.
  • Stage IIIB – The tumor extended through the prostatic capsule to the seminal vesicles or the adjacent structures, such as the bladder, muscles or the pelvic floor (T3-4). There is no regional lymph node metastasis and no distant metastasis. (N0/M0). There can be any PSA level. The Grade Group is 1-4.
  • Stage IIIC – The tumor may or may not be extended through the prostatic capsule but has not spread to the regional lymph nodes or to other distant areas (N0/M0). There can be any PSA level. The Grade Group is 5.
     
     

Stage 4 Prostate Cancer

In stage 3, cancer has now spread beyond the prostate and may have potentially spread into the nearby seminal vesicles.

  • Stage IVA – The tumor may have any size and has already spread to the regional lymph nodes(N1) but has not spread to other distant areas (M0). There can be any PSA level and any Grade Group.
  • Stage IVB – The tumor may have any size and presents distant metastasis (M1), without involving the lymph nodes (N0). There can be any PSA level and any Grade Group.
     

Prostate cancer survival rates

Prostate cancer is the second leading cause of cancer death in the United States. A man’s individual survival depends on the stage of cancer. Most prostate cancers (90%) are identified at an early stage when they are organ-confined. According to the American Cancer Society, the 5-year survival rate for men with local or regional prostate cancer is nearly 100%. The relative 10-year survival rate is 98% and the 15-year relative survival rate is 91%.

However, if the cancer is stage IVB and has spread to distant parts of the body such as the lungs, liver, or bones there is only a 30% relative 5-year survival rate.

Things to consider when understanding the statistics:

  • These numbers/rates apply only for the first-diagnosed cancer
  • There are many more factors that can influence the survival rate of an individual (PSA level, overall health, age)
  • These rates are calculated over a 5-year period. Treatments improve over time and the survival rates may positively change.

Early detection makes this deadly disease curable. Do not ignore any prostate cancer signs or symptoms and get screened as early as possible, especially if you are at high risk of developing prostate cancer, based on your family history, race or age. Talk to your doctor about your Gleason Score, Grade Group and Stage and decide upon the best treatment option for prostate cancer.

Bibliography

  1. TNM Staging, Cancer Research UK, Web
  2. Prostate cancer: diagnosis and staging, PubMed, Web, 1 Dec 2018
  3. The prostate cancer staging guide, Prostate Cancer Research Institute, Web
  4. Prostate Cancer Stages, Johns Hopkins Medicine, Web
Dr. David Samadi | Robotic Prostate Surgeon

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