- Gleason score
A Gleason score is given to
prostate cancer based upon itsmicroscopic appearance. Cancers with a higher Gleason score are more aggressive and have a worseprognosis .Most often, a urologist will remove a cylindrical sample (
biopsy ) of prostate tissue through the rectum, using hollow needles, and prepare microscope slides. After a prostate is removed in surgery, a pathologist will slice the prostate for a final examination.The pathologist assigns a "grade" to the most common tumor, and a second "grade" to the next most common tumor. The two "grades" are added together to get a Gleason "score". For example, if the most common tumor was grade 3, and the next most common tumor was grade 4, the Gleason "score" would be 3+4 = 7.
The Gleason grade is also known as the Gleason pattern and the Gleason score is also known as the Gleason sum.
In the UK, prostate cancer of Gleason pattern 1 and 2 are almost never seen. Gleason pattern 3 is by far the most common.
The Gleason "grade" ranges from 1 to 5, with 5 having the worst prognosis. The Gleason "score" ranges from 2 to 10, with 10 having the worst prognosis.
It should be noted that for Gleason score 7, a Gleason 4+3 is a more aggressive cancer than a Gleason 3+4. Also, there is not really any difference between the aggressiveness of a Gleason score 9 or 10 tumour.
Gleason scores are associated with the following features:
* Grade 1 - The cancerous prostate closely resembles normal prostate tissue. The glands are small, well-formed, and closely packed
* Grade 2 - The tissue still has well-formed glands, but they are larger and have more tissue between them.
* Grade 3 - The tissue still has recognizable glands, but the cells are darker. At highmagnification , some of these cells have left the glands and are beginning to invade the surrounding tissue.
* Grade 4 - The tissue has few recognizable glands. Many cells are invading the surrounding tissue
* Grade 5 - The tissue does not have recognizable glands. There are often just sheets of cells throughout the surrounding tissue.A
pathologist examines the biopsy specimen and attempts to give a score to the two patterns. First called the primary grade, represents the majority of tumor (has to be greater than 50% of the total pattern seen). Second - a secondary grade - relates to the minority of the tumor (has to be less than 50%, but at least 5%, of the pattern of the total cancer observed). These scores are then added to obtain the final Gleason score.Increasingly, pathologists provide details of the "tertiary" component. This is where there is a small component of a third (generally more aggressive) pattern. So there could be a Gleason 3+4 with a tertiary component of pattern 5 - this would be considered to be more aggressive than a prostate cancer that was Gleason 3+4 with no tertiary pattern 5. Although it is debateable as to what the full extent the tertiary component has on the aggressiveness of a cancer.
The Gleason score is used to help evaluate the prognosis of men with prostate cancer. Together with other parameters, the Gleason score is incorporated into a strategy of
prostate cancer staging which predicts prognosis and helps guide therapy.The scoring system is named after Donald F. Gleason, M.D., a pathologist at the Minneapolis Veterans Affairs Hospital who developed it with other colleagues at that facility in the 1960s. [ [http://www.urologytimes.com/urologytimes/article/articleDetail.jsp?id=325501 Manage Account - Modern Medicine ] ] It remains an important tool.
References
* [http://www.medscape.com/viewarticle/406837 Minimal Adenocarcinoma in Prostate Needle Biopsy Tissue,] Phataraporn Thorson, MD, and Peter A. Humphrey, MD, PhD, Am J Clin Pathol 114(6):896-909, 2000. Pathology slides and explanation. [Free]
* [http://www.gfmer.ch/selected_images_v2/detail_list.php?cat1=13&cat3=749&stype=d WHO, Geneva Foundation for Medical Education and Research, Prostate cancer, Gleason score.] 51 images.
*Gleason DF. "The Veteran's Administration Cooperative Urologic Research Group: histologic grading and clinical staging of prostatic carcinoma." In Tannenbaum M (ed.) Urologic Pathology: The Prostate. Lea and Febiger, Philadelphia, 1977; 171-198.
* [http://www.malecare.com Prostate Cancer Information website, nonprofit, updated weekly]
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