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How is Prostate Cancer Staged and Graded?

May 25, 2021 | by
introduction

How is Prostate Cancer Staged and Graded?

According to the World Cancer Research Fund, prostate cancer is the second most common cancer that occurs in men. It is also the fourth most common cancer that occurs overall. Cancer.net has also predicted that an estimated 248,530 men will be diagnosed with this condition in the United States in 2021. Like other cancers, treating prostate cancer can be a challenge. However, early diagnosis can make a world of difference. For instance, if you get diagnosed with early-stage prostate cancer, your 5-year survival rate is higher than 99%. Patients that opt for a radical prostatectomy can also maintain very good health. This procedure can extend their life expectancy by 10 to 15 years. The cause-specific survival rates here are 82% to 90%, and metastasis-free survival rates are 76% and 82%. The survival rates for local recurrence-free cases are also 75% and 83%. In this article, we will discuss the staging of prostate cancer and its various grades under the Gleason score system.

Staging

The Staging of Prostate Cancer

There are two types of staging that apply to prostate cancer. These include:

1. Clinical Staging

Clinical staging uses information from the Gleason score assigned and the results of your PSA and DRE tests. These tests are used to screen for prostate cancer. The PSA test is a type of blood test that measures prostate-specific antigen levels in your blood. The DRE test is a digital rectal exam that involves examining an individual’s pelvis, lower rectum, and lower stomach area. It allows a doctor to check for health problems such as prostate cancer.


Based on the results of these tests, your doctor can recommend the need for further testing, x-rays, CT scans, bone scans, MRI, etc.

2. Pathologic Staging

Pathologic staging of prostate cancer is based on the information you find during surgery. It also includes the lab results of any prostate tissue that has been removed during the surgery. The surgeon may remove the entire prostate here, along with some lymph nodes. The lymph nodes removed can prove to be a valuable source of information for pathologic staging.

Tumor, Node, and Metastasis

The TNM System for Staging Prostate Cancer

Image Description: Staging of prostate cancer based on the TNM system

T1, T2, and T3 stages of prostate cancer TNM is short for Tumor, Node, and Metastasis. The TNM system helps you identify the current stage of your prostate cancer and develop a treatment plan. Your Gleason score is also an important consideration for this. We will discuss it in a later section.

Artwork attribution: Cancer Research UK / Wikimedia Commons
System for Staging Prostate Cancer

Tumor

This describes the size of the tumor. There are 4 stages used to identify the cancer size here. These include:

T1

At this stage, the size of the tumor is too small to be visible on a scan. It cannot be felt during a prostate examination, as well. It is further divided into:

 

T1a: The cancer is present in less than 5% of the tissue removed from your prostate. It is not visible, but your surgeon may find T1a cancers during the procedure.

 

T1b: The cancer is present in 5% or more of the tissue removed from the prostate

 

T1c: The cancer has been detected in a biopsy

T2

At this stage, the cancer is present inside your prostate gland. It can be further divided into:

 

T2a: This indicates that the cancer is occupying space in only one half of the prostate and is present on only one side.

 

T2b: This suggests that the cancer is occupying more than one-half of the prostate but is still present on one side.

 

T2c: This shows that the cancer is present in both sides of the prostate gland but hasn’t extended further.

T3

At this stage, the cancer has extended beyond the gland capsule. It is further divided into:

 

T3a: This means the cancer has moved past the gland capsule but has not spread into the seminal vesicles (tubes carrying semen)

 

T3b: This means that the cancer has entered the seminal vesicles.

T4

This stage suggests that the cancer has spread to other organs and body parts such as the bladder, the pelvic wall, etc.

System for Staging Prostate Cancer

Node

This indicates if the cancer has extended to the lymph nodes. There are two observations here.
The first is N0, which suggests that there are no cancer cells in nearby lymph nodes.
The second is N1, which indicates the lymph nodes located near the prostate carry cancer cells.

System for Staging Prostate Cancer

Metastasis

Metastasis refers to the stage where the cancer has extended to other parts of the body. There are 2 stages to consider here. The first is M0, which indicates that the cancer is confined to the prostate and hasn’t spread to other body parts. The second is M1, which suggests that the cancer is present in other body parts outside the pelvis. You can split this stage into 3 parts:

M1a: This suggests the presence of cancer cells in the lymph nodes present outside the pelvis.
M1b: At this stage, the cancer cells have spread into the bone.
M1c: This stage indicates that cancer cells are present in other body parts.

The Gleason Score for Prostate Cancer The Gleason score is a type of system used to grade prostate cancer. It is used to discern the appearance of cancer cells and determine if they look like normal cells. The Gleason Score is divided across 5 grade groups. These include:

Grade Group 1

Gleason Score: 6

This is the least aggressive stage where the cancer cells appear similar to normal cells and are well-differentiated. The cancer will grow at a very slow rate at this stage.

Grade Group 2 and 3

Gleason Score: 7

For Grade Group 2, a majority of the cancer cells look similar to normal cells. You can still expect the cancer to grow slowly in this case.

In the case of Grade Group 3, the cells are not that well-differentiated and do not bear a close resemblance to normal prostate cells. The cancer can grow at a moderate rate here.

Grade Group 4

Gleason Score: 8

At this stage, some of the cells have an abnormal appearance, and the cancer can grow at a fast or moderate rate.

Grade Group 5

Gleason Score: 9 or 10

The cells are poorly differentiated at this stage and look highly abnormal. We can expect the cancer to advance at an exponential rate here.

Recommendation

Conclusion

It can be difficult to understand the staging of prostate cancer and how Gleason scores work. A doctor will primarily consider the size of the cancer, the stage, the patient’s PSA level, and their age and health condition.

We recommend getting in touch with a medical professional specializing in the treatment of prostate cancer for more information on this.

Disclaimer: This blog post is provided for informational purposes and is not intended to replace the guidance of your personal physician. Please consult a medical professional if you have any concerns after reading this or other blog posts on this website.