The Gleason Score Explained

Gleason score is named after Dr. Donald Gleason. It is used to evaluate the prognosis of men with prostate cancer. Depending upon the microscopic appearance of prostate cancer, gleason score is given. Gleason score along with other parameters can predict the prognosis and guided therapy can be given for prostate cancer.

A biopsy is generally taken of a prostate tissue through the rectum using hollow needles and a slide is prepared to study the sample.

For analyzing a prostate cancer, a categorical scoring system is required which helps the doctor to know the overall health if the prostate gland. It also helps to determine the presence and severity of the prostate cancer.

Grades and scores:

A grade is assigned to the most common tumor pattern. A second grade is assigned to the next most common tumor pattern. The two grades are then added together to get a gleason score. This score is given by a pathologist. A gleason score maybe between 2 to 10.

Following features are seen associated with gleason pattern:

Pattern 1- the cancerous tissue closely resembles the normal prostate tissue. The glands are well formed, small in size and closely packed.

Pattern 2-the glands are well formed. They appear larger and have more tissue between them.

Pattern 3-the cells appear dark. At a higher magnification, some cells appear to invade the surrounding tissue. The tissue still has recognizable glands.

Pattern 4-many cells are seen invading the surrounding tissues. The tissue hardly has any recognizable glands.

Pattern 5-sheets of cells are seen invading the surrounding tissue. The tissue does not show any recognizable glands.

The biopsy specimens are studied by the pathologist. He gives a score to the two patterns.

-primary grade: this represents majority of the tumor. That is more than 50% of the tumor.

-secondary grade: this represents the minority of the tumor. That is less than 50% but at least 5% of which is cancerous.

-tertiary grade: most pathologists include the tertiary grade which includes a small component of a more aggressive pattern.

These scores are then added to the final gleason score.

The defects in this scoring system are as follows:

The gleason grading and scoring system is largely subjective. The range of gleason score diagnosed has come down to where almost all patients today presents with a gleason score of 6, 7 or 8.

When a small, thin needle core tissue samples are obtained from a biopsy not all pathologists are equally proficient in reading gleason grades.

In today’s changing patterns of presentation of prostate cancer, the gleason score is not the only key statistic available from the patient’s biopsy.

Errors in predicted biopsy gleason score are common and often result in under grading of the tumor.



An accurate prognosis is not a gleason score alone. A complete and a thorough interpretation of all the clinical and pathological information available from a biopsy material are necessary.

The gleason score should be read only by an experienced uropathologist or a laboratory known for its focus on urology.

A prostate cancer pathology expert can generally read the gleason score well and accurately interpret the biopsies.

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