What Is the Gleason Score?

Gleason classification is a widely used method for histological classification of prostate cancer. Because Gleason classification is well correlated with biological behavior and prognosis, it is gradually recognized and used more and more widely, and it has become an important reference index for the development of prostate cancer treatment programs. Since the 1990s, Gleason classification, prostate-specific antigen (PSA) levels, and tumor staging are the most important indicators for determining treatment options in the prostate cancer treatment guidelines recommended by the American Cancer Network. The 2004 edition of the WHO Classification of Urinary and Male Reproductive System Tumors has included Gleason classification.

Due to Gleason classification and biological behavior and

A five-stage method closely related to prognosis was used.

According to the degree of gland differentiation, grade 5 (grade 1 with 1 point, well differentiated; increase by 1 point for each progressive 1 grade; grade 5 with 5 points, undifferentiated).

For variations in the structure of adenocarcinoma in different regions of the same tumor, score them according to the degree of primary and secondary differentiation, and use the total score of the two scores as the criterion for judging the prognosis (for example, the main structure of adenocarcinoma is rated as 2 points, times If the structure is rated as 4 points, the points will be 2 + 4 = 6 points; if there is only 1 structure type and the score is 3 points, the points will be 3 + 3 = 6 points;

The Gleason grading system is very reproducible, with a consistency of 80% to 90%. The most common cause of inconsistency is that the tumor is between two gradings. Although it is more common, or even unavoidable, to undergrade biopsy rather than overgrade due to specimen errors, the consistency of the Gleason score of the punctured tissue with the results of subsequent prostate cancer specimens is quite good. Approximately 3% of specimens with Gleason scores of 2 to 4 are generally found in prostate puncture specimens, which is consistent with the incidence of low-grade cancers in radical specimens.

After many years, some people's low-grade tumors developed into high-grade tumors. It is unclear whether the residual low-grade tumors progressed or another multifocal, more aggressive tumor appeared; tumors. Although the classification of large tumors is high and the classification of small tumors is low, there are always exceptions. There is a hypothesis that the tumor starts from a low grade and then differentiates into a high grade cancer after reaching a certain volume. Another argument is that high-grade tumors may be high-grade at the beginning, because they grow rapidly and are larger in volume at the time of discovery, while low-grade tumors are smaller in size at the time of discovery due to slow development.

The disadvantage of Gleason classification is that it is classified according to the tissue structure of the tumor, regardless of the type of cytology, which may be closely related to prognosis. ; Another disadvantage is that the repeatability will vary depending on the scales that pathologists have. ^[2]

A pathologist examines the biopsy specimen under a microscope for certain "Gleason" modes. The following characteristics are related to these Gleason models:

Pattern 1-Normal prostate tissue is similar to prostate cancer. Small glands, well-formed and dense. This corresponds to a highly differentiated cancer.

Mode 2-The tissue still has well-formed glands, but they are larger and have more tissue, which means that the stroma has increased. This also corresponds to a moderately differentiated cancer.

Pattern 3-The tissue still has recognizable glands, but the cells are darker. At high power, these cells have left the glands and have begun to invade surrounding tissues or have permeable patterns. This corresponds to a moderately differentiated cancer.

Pattern 4-The tissue has few identifiable glands. Many tumor cells invade surrounding tissue masses. This corresponds to a poorly differentiated cancer.

Pattern 5-The tissue has no or only few identifiable glands. There are often sheets of cells throughout the surrounding tissue. This corresponds to an undifferentiated cancer.

In the Gleason system form, Gleason models 1 and 2 of prostate cancer are rare. Gleason pattern 3 is the most common.

Pathologists define the grade of the tumor.

Low level-the main pattern assigned to the tumor (must be greater than 50% of the total pattern).

Intermediate-assigned to the next most frequent pattern (must be less than 50%, but at least 5% of all cancer patterns observed).

Advanced-More and more pathologists provide details of "tertiary" components. Here's a small component one-third (usually more aggressive) pattern.

The pathologist's model then summarized the primary and middle school results to obtain the final Gleason score. If you only see two patterns, the score for the first number is the primary grade for the tumor and the score for the second number is the medium grade, as described in the previous section. If you see three patterns, the score for the first number will be the main grade and the number of patterns with the second highest grade. For example, if the primary tumor is grade 2 and the secondary tumor is grade 3 but some cells are found to be grade 4, the Gleason score will be 2 + 4 = 6. This is a subtle change from the Gleason system before 2005, and the second number is the secondary level (ie, the second most common cell line pattern). There is a Gleason score of 3 + 4 for the three-level component mode 5-this would be considered more aggressive for prostate cancer, and a Gleason score of 3 + 4 does not have the third-level mode 5. However, the full meaning of the third component of aggressive cancer is controversial.

Gleason scores range from 2 to 10, with 2 representing the most well-differentiated tumors and 10 least-differentiated tumors. Gleason scores are often divided into groups showing similar biological behavior: low grade (well differentiated), chest, mildly poorly differentiated or high grade. A database (1982-2011) investigating Johns Hopkins radical prostatectomy presented a Gleason score and prognostic group: Gleason score 6 (prognosis group I); Gleason score 3 + 4 = 7 (prognosis group II); Gleason score 4 + 3 = 7 (prognosis group III); Gleason score 4 + 4 = 8 (prognosis group 4); Gleason score 9 (prognosis group V) . Prostate cancer and Gleason scores 6 usually have fairly good predictions.

Gleason architecture model and Gleason grade are interchangeable.

Gleason class / has two main points:

1. Based on architectural patterns, not cytology. The building function of the Gleason system is divided into 15 histological models. These are reducing differentiated orders but growing in number: Mode 1 is the most differentiated and Mode 5 is at least different.

(Poorly differentiated "cancer" is usually a poor prognosis. Differentiated tissue, usually referring to tumors, is similar to native tissue. So less similarities are usually a poor prognosis.)

2. The second feature of the Gleason score is that the grade is not based on the highest (at least differentiated) pattern in the tumor, but instead is the usual combination and the second most common pattern. Gleason found that prostate cancer has multiple patterns and that the prognosis of prostate cancer is the most prevalent and the second most common tumor pattern. So using the Gleason system, the most common and most common model, if at least 5% of the tumors, add up is equivalent to the entire Gleason score.

If for example the most common pattern / is 2 and the second most popular is 1, then the Gleason score is 2 + 1 = 3. If the tumor has only one pattern, the number of that pattern doubles to reach a score. For example, tumors are all mode 1, Gleason score 1 + 1 = 2. The most differentiated tumor will, at the highest, Gleason score of 2 (type 1 architecture of 1 + 1 will double), while the most severely differentiated tumor (unlike native prostate tissue) will have a 10 (5 +5 is also organized by all type 5). So the Gleason score / level can only be 2-10, there is no definition of 0 or 1.

The prostate gland usually has two layers of glandular cells. In adenocarcinoma (adeno-this is adenocarcinoma, cancer-its ectoderm is derived because only the tissue of the ectoderm makes the glands) basal ) The cell layer is missing so that you only have one cell with the top layer usually from a columnar-pseudostratified appearance.

Score description

Using this system the highest differentiated tumor Gleason score / grade 2, and the least-differentiated tumor 10 points. The definition of the range is 2-10, building types from 1-5 and always double or add together so as mentioned above. Gleason scores are usually grouped based on similar behaviors: grades 2-4 are well-differentiated tumors, grades 5-6 thoracic tumors are moderate 7-moderately differentiated tumors are grade 8-10 high-grade tumors.

Gleason 1

Gleason pattern 1 is the pattern of the most well-differentiated tumors. It is a well-defined single / independent nodule, close / dense, back-to-back gland pattern and does not invade adjacent healthy prostate tissue. The glands are round and oval in shape and large in proportion. Comparing them to Gleason Model 3 tumors, they are approximately equal in size and shape.

Gleason 2

Gleason 2 has rather single confined nodules, separate glands. However, the glands are loosely arranged and there is no uniform pattern1. Minimal invasion may be seen through the surrounding healthy prostate glandular tissue. Similar to Gleason 1, Gleason 3's glands are usually more patterned than those, and rounded oval shapes. So the main difference between Gleason 1 and 2 is that the packing glands and the density of invasion are possible in Gleason 2 and not defined in Gleason 1.

Gleason 3

Gleason 3 is a clearly invasive tumor that spreads to adjacent healthy prostate tissue. The glands are alternate in size and shape, usually long / horned. They are usually small / micro-glandular Gleason compared to a score of 1 or 2. However, some are medium-sized. Gleason's small glands, which are smaller and have a defined pattern4, are different glandular units. Spiritually you can draw a circle for each glandular unit Gleason 3.

Gleason 4

Gleason pattern 4 glands are no longer single / separated glands with patterns 1-3. They are fused together and difficult to distinguish, rare cavities and Gleason 1-3 usually have open lumens (spaces) inside the glands, or they can be sieve-like (similar to a sieve sieve plate / similar. One item There are many perforations). Fusion glands are chains, nests or groups of glands that are no longer completely made up of the stroma-(connective tissue separates individual glands usually in this case). Glandular fusion consists of "partially" isolated glands that are occasionally given by the stroma. Due to this separation, the fusion glands sometimes have a fan-shaped (think of a slice of bread and a bite) appearing on their edges.

Gleason 5

There is no adenocarcinoma differentiation (thus unlike normal prostate tissue). It consists of a table (groups of cells that look almost flat like a box), solid ropes (groups of cells like fashion running through other tissue / cell patterns), or individual cells. You should not see a round of glandular cavity space, you can see similar other types of more normal prostate appearance.

Prognosis

Gleason scores 2-4 are usually found in smaller tumors located in the transition area (urethra). These are usually the precursor lesions found by the way for benign prostatic hypertrophy surgery (note: not prostate cancer).

Most cancers / treatments are assessed with a Gleason score of 5-7 and detection of abnormal rectal or prostate specific antigens due to abnormalities after biopsy. Cancer is usually located in the posterior part of the peripheral area, explaining the basic principles of performing the rectum.

Tumors with a Gleason score of 8-10 are often advanced tumors and cannot be cured. Although some evidence suggests that prostate cancer will become more aggressive over time, most often Gleason scores remain stable for several years.

There are many kinds of pathological grading systems for prostate cancer. Gleason grading system (Gleason grading systen) is the most widely used grading system at home and abroad, clinically and pathologically. This system was proposed by Gleason in 1966, and then revised twice in 1974 and 1977. The Gleason score method is based on the degree of differentiation of the glands and the growth mode of the tumor in the interstitial as the criteria for the evaluation of the malignancy of the tumor.At the same time, the prostate cancer tissue is divided into a primary classification area and a secondary classification area. It refers to the growth method that dominates the area, and the secondary hierarchical area refers to the growth method that does not occupy the main area but accounts for at least 5% of the area. The Gleason score of each zone is 1 ~ 5. The Gleason score is the sum of the Gleason scores of the major graded zone and the minor graded zone to form the cancer tissue graded constant. Its characteristics can be summarized as: 1 grading principle (growth mode), 2 aspects (main growth mode and secondary growth mode), 5-level system (gland differentiation degree 1-5 grade), 10 points (worst differentiation) (5 + 5 = 10) ^[3] .