Prostate Cancer Grading & Prognostic Scoring
The Gleason Score is the grading system used to determine the aggressiveness of prostate cancer. This grading system can be used to choose appropriate treatment options.
The Gleason Score ranges from 1-5 and describes how much the cancer from a biopsy looks like healthy tissue (lower score) or abnormal tissue (higher score). Most cancers score a grade of 3 or higher.
Since prostate tumors are often made up of cancerous cells that have different grades, two grades are assigned for each patient. A primary grade is given to describe the cells that make up the largest area of the tumor and a secondary grade is given to describe the cells of the next largest area. For instance, if the Gleason Score is written as 3+4=7, it means most of the tumor is grade 3 and the next largest section of the tumor is grade 4, together they make up the total Gleason Score. If the cancer is almost entirely made up of cells with the same score, the grade for that area is counted twice to calculated the total Gleason Score.
Typical Gleason Scores range from 6-10. The higher the Gleason Score, the more likely that the cancer will grow and spread quickly.
- Scores of 6 or less describe cancer cells that look similar to normal cells and suggest that the cancer is likely to grow slowly.
- A score of 7 suggests and intermediate risk for aggressive cancer. Scoring a 7 means that the primary score (largest section of the tumor) scored a 3 or 4. Tumors with a primary score of 3 and a secondary score of 4 have a fairly good outlook, whereas cancers with a primary Gleason Score of 4 and a secondary score of 3, are more likely to grow and spread.
- Scores of 8 or higher describe cancers that are likely to spread more rapidly, these cancers are often referred to as poorly differentiated or high grade.
How Important is the Gleason Score?
The Gleason Score is very useful for predicting the behavior of a prostate cancer. However, other factors also contribute to determining the stage of prostate cancer, including:
- The PSA level
- Findings from a rectal exam
- The number of biopsy core samples that contain cancer
- The percentage of cancer making up each biopsy core sample
- If cancer is found in one or both sides of the prostate
- If the cancer has spread outside the prostate
How Important Is the Gleason Score?
The Gleason Score is very important in predicting the behavior of a prostate cancer. Still, other factors are also important such as:
- The PSA Level
- Findings on a rectal exam
- How much of each core is made up of cancer
- The number of cores that contain cancer
- Whether cancer was found in both sides of the prostate
- Whether the cancer has spread outside the prostate
What does it mean to have a Gleason Score of 6 or 7 or 8-10?
The lowest Gleason Score of a cancer found on a prostate biopsy is 6. These cancers may be called well-differentiated or low-grade and are likely to be less aggressive - they tend to grow and spread slowly.
Cancers with Gleason Scores of 8 to 10 may be called poorly differentiated or high grade. These cancers tend to be aggressive, meaning they are likely to grow and spread more quickly.
Cancers with a Gleason Score of 7 may be called moderately differentiated or intermediate grade. The rate at which they grow and spread tends to be in between the other 2.
My Gleason Score Looks Different
Other ways that this Gleason Score may be listed in your report are Gleason 7/10, Gleason 7 (3+4) or combined Gleason Grade of 7.
What does it mean when there are different core samples with different Gleason Scores?
Cores may be samples from different areas of the same tumor or different tumors in the prostate. Because the grade may vary within the same tumor or between different tumors, different samples (cores) taken from your prostate may have different Gleason Scores. Typically, the highest (largest number) Gleason Score will be the one used by your doctor for predicting your prognosis and deciding treatment.
Can the Gleason Score on my biopsy really tell what the cancer grade is in the entire prostate?
Prostate biopsies are tissue samples from different areas of the prostate. The Gleason Score on a biopsy usually reflects the cancer's true grade. However, it is possible that the Gleason Score from your biopsy is lower or higher than the true grade. To reduce the risk of over-or-under scoring, multiple biopsies are usually taken from different areas within the prostate.
What does it mean if my biopsy mentions that there is perineural invasion?
Perineural invasion means that cancer cells were seen surrounding or tracking along a nerve fiber with the prostate. When this is found on a biopsy, it means there is a higher chance that the cancer has spread outside the prostate. Still, perineural invasion does not mean that the cancer has spread, and other factors, such as the Gleason Score and amount of cancer in the cores are more important. In some cases, findings perineural invasion may affect treatment, so if your report mentions perineural invasion, you should discuss it with your doctor.
What does it mean if my biopsy report also says high-grade prostatic intraepithelial neoplasia or high-grade PIN?
High-grade prostatic intraepithelial neoplasia (or high-grade PIN) is a pre-cancer to the prostate. In this instance, high-grade refers to the PIN and not the Gleason Score.
What does it mean if, in addition to cancer, my biopsy report also says atypical glands or atypical small acinar proliferation (ASAP) or glandular atypia or atypical grandular proliferation?
All of these terms mean the pathologist saw something in your biopsy that suggests cancer may be present, but they cannot be certain. For individuals with known prostate cancer this is no longer relevant.
What does it mean if in addition to cancer my biopsy report also says acute inflammation (acute prostatitis) or chronic inflammation (chronic prostatitis)?
Inflammation of the prostate is called prostatitis. Most cases of prostatitis reported on a biopsy are not caused by infection and do not need to be treated. In some cases, inflammation may increase you PSA level, but it is not linked to prostate cancer. The finding of prostatitis on a biopsy of someone with cancer does not affect their prognosis or the way the cancer is treated.
New Prostate Cancer Grading System: The new prostate grading system is an extension of the current Gleason grading scale for determining the stage of prostate cancer. This system is designed to provide a simplified and more accurate grading stratification system than the current Gleason Score. This new method is especially focused on better representing low grade disease to reduce unnecessary treatment of indolent prostate cancer. The new grading system subdivides prostate cancer into five categories using pathological characteristics as described in the table below.