Staging and Grading

Prostate cancer can only be diagnosed with a biopsy. Once prostate cancer is confirmed, it’s important to learn about the stage (location) and the grade (aggressiveness) of the tumor.

Staging Prostate Cancer

Prostate cancer staging is the process used to find out if the cancer has spread within the prostate or to other parts of the body. Knowing the stage of your prostate cancer is very important. It can help you more accurately talk about your prostate cancer and discuss treatment options with your treatment team. The process of staging involves a biopsy of the prostate cells, as well as imaging scans like ultrasound, MRI scans, and CT scans. The stages of prostate cancer are:

The above prostate cancer staging chart may be helpful to you, but sometimes people refer to their prostate cancer using one of the terms below:

• Localized prostate cancer – the prostate cancer has not spread outside the prostate
• Locally advanced prostate cancer – the prostate cancer has traveled just outside the prostate, sometimes to nearby lymph glands or to the seminal vesicles
• Advanced prostate cancer – the prostate cancer has spread beyond the prostate to distant organs or to the bones; this is also called metastatic prostate cancer

Grading Prostate Cancer

The grade of the prostate cancer is also called the Gleason score. This score is used to estimate if and how quickly the tumor will grow and spread. The Gleason score is determined by looking at the tumor cells from the biopsy under a microscope. The pathologist assigns a number to the cells based on how abnormal they appear. The scale goes from 1 (non-aggressive) to 5 (very aggressive). The numbers of the two most common patterns are added together to create a Gleason Score. The Gleason grading system is one of the most important prognostic factors (that will help determine outcomes) in prostate cancer.[1]

For example, in a biopsy where the most common cell type is a 3, and the second most common cell type is a 4, is a Gleason score 7. However, a biopsy where the most common cell type is a 4 and the second most common cell type is a 3 would also be considered a Gleason score 7. However, it is important to know that a 3+4 can progress very differently than a 4+3.[1] The chart below describes the Gleason grading system:

What does staging and grading mean for treatment?

The prostate cancer stage and grade are important for determining your course of treatment. Some treatments are only effective for Stage I and II prostate cancer and other treatments are only necessary for Stage III and IV prostate cancer.

Grading is especially useful in early-stage disease. If the tumor shows signs of being aggressive, it may make sense to go forward with more aggressive prostate cancer treatment options. If the tumor does not seem aggressive, it may make sense to go forward with active surveillance or watchful waiting and avoid common side effects.

In any case, the stage and grade must be discussed with your doctor and healthcare team.

More detail on prostate cancer staging —

The standard Tumor, Node, and Metastasis (TNM) system is used to stage prostate cancer. The T category is based on the extent of the tumor itself. The N category is based on whether the cancer has spread to nearby lymph nodes. The M category is based on whether the cancer has spread beyond nearby lymph nodes to distant organs.

T (Tumor) Categories:

• T1: the tumor cannot be felt with a DRE or seen with imaging
  • T1a: the tumor is found accidentally during a surgery for benign prostatic hyperplasia or another prostate condition. The tumor takes up less than 5% of the removed tissue
  • T1b: the tumor is found accidentally during a surgery, and the tumor takes up more than 5% of the removed tissue
  • T1c: the tumor is diagnosed with a needle biopsy, usually because of an elevated PSA
• T2: the tumor is confined to the prostate and can be either felt with a DRE or seen with imaging
  • T2a: the tumor is confined to half of one lobe of the prostate
  • T2b: the tumor is present to more than half of one lobe, but is not in both lobes
  • T2c: the tumor is present in both lobes of the prostate
• T3: the tumor has grown outside of the prostate and may be present in the seminal vesicles
  • T3a: the tumor is outside of the prostate, but is not in the seminal vesicles
  • T3b: the cancer is outside of the prostate and has spread to the seminal vesicles
• T4: the tumor has grown into tissues beyond the seminal vesicles

N (Node) Categories:

• NX: nearby lymph nodes were not checked for cancer
• N0: the tumor is not present in nearby lymph nodes
• N1: the tumor has spread to one or more nearby lymph nodes

M (Metastasis) Categories:

• M0: the cancer is not present in other parts of the body beyond the nearby lymph nodes
• M1: the cancer is present in the body beyond the nearby lymph nodes
  • M1a: the cancer has spread to distant lymph nodes
  • M1b: the cancer has spread to the bones
  • M1c: the cancer has spread to other organs

Each of the stages is based on some combination of these categories.

Stage I:

• The tumor cannot be felt with a DRE or seen with imaging (T1), and the PSA is less than 10 ng/mL, with a Gleason score of 6 or lower; OR
• The tumor can be felt with a DRE or seen with imaging, but is confined to half of one lobe (T2a), and the PSA is less than 10 ng/mL, with a Gleason score of 6 or lower; OR
• The tumor is either in T1 or T2a, but the PSA and Gleason score are unknown

Stage IIA:

• The tumor cannot be felt with a DRE or seen with imaging (T1), or the tumor is confined to half of one lobe (T2a), and the PSA is less than 20 ng/mL, with a Gleason score of 7; OR
• The tumor is either in T1 or T2a, and the PSA is equal or more than 10 ng/mL but less than 20 ng/mL, with a Gleason of 6 or lower; OR
• The tumor is present to more than half of one lobe, but is not in both lobes (T2b), and the PSA is less than 20 ng/mL, with a Gleason score of 7 or lower; OR
• The tumor is present to more than half of one lobe, but is not in both lobes (T2b), and the PSA and Gleason score are unknown

Stage IIB:

• The tumor is present in both lobes of the prostate (T2c), with any PSA and any Gleason score; OR
• The tumor is either in T1 or T2, and the PSA is equal or less to 20 ng/mL, with any Gleason score; OR
• The tumor is either in T1 or T2, with any PSA and a Gleason of 8 or higher

Stage III:

• The tumor has grown outside of the prostate and may be present in the seminal vesicles (T3), with any PSA and any Gleason score

Stage IV:

• The tumor has grown into tissues beyond the seminal vesicles, with any PSA and any Gleason score, OR
• The tumor has spread to one or more nearby lymph nodes, without metastases, with any PSA and any Gleason score; OR
• The cancer is present in the body beyond the nearby lymph nodes, in tissues like the bone or distant organs, with any PSA and any Gleason score

What are the D’Amico risk categories?

The D’Amico system provides an estimate of the risk of recurrence at five years after treatment. This system is one of the most widely used for risk assessment. It combines the PSA, Gleason score, and the clinical stage to create low, intermediate, and high risk categories. The higher the risk category, the higher the chance of recurrence is five years after treatment.

The D’Amico risk categories are below. If one factor is putting you in a lower category but another is putting you in a higher category, then the higher category takes precedent.

Low Risk:

• PSA is less than 10 ng/mL AND
• Gleason score is equal to or less than 6 AND
• Clinical stage T1-T2a

Intermediate Risk:

• PSA is between 10 and 20 ng/mL OR
• Gleason score is 7 OR
• Clinical stage T2b

High Risk:

• Gleason score is 8-10 OR
• PSA is greater than 20 ng/mL OR
• Clinical stage T2c-T3