Gleason Grading System
The Gleason score is the histological ( histological ) assessment of prostate cancer (see: grading). Here, the so-called Entdifferenzierungsgrad (ie, deviation from normal tissue ) of the most common and is the second most common cell population of the tumor assessed. For microscopic assessment is material of a prostate core biopsy or an already surgically removed prostate. In this case, values from 1 to 5 are given for both cell populations. The higher the value, the higher is the degree of dedifferentiation. The specification is based on the pattern: Gleason score 1 value 2 = sum of the two values .
The scoring system was developed in the 1970s by the American pathologist Donald F. Gleason and later named after him.
Assessment of Gleason score
The division comprises five levels, with Level 1 the most differentiated tumors and grade 5 describes the worst- differentiated tumors whose growth patterns have lost almost all resemblance to normal prostate tissue. The grades 2-4 are in between.
The Gleason score is always formed from two such degree graduations, the first named in the punch biopsy the most abundant degree (main growth pattern ) and the second the second most ( sub-pattern, which takes at least 5% of the carcinoma ) describes occurring Gleason grade. Is already the entire prostate is removed, the Gleason score is calculated here using the two most common Gleason grade. If there is only one growth pattern, so the degree is doubled. In this scheme, thus describes the score 1 1 = 2, the best -differentiated tumors, the score 5 5 = 10 represents the worst combination dar.
The more common and more important for diagnostic purposes the case of determination of the Gleason score is the examination of tissue material by a pathologist, which the urologist removed by punch biopsy of the prostate. Since a biopsy always only a small portion of the tumor is removed, the diagnosis of a Gleason grade 1 or 2 in the punch, however, generally is not possible. Therefore, the lowest score is in the punch biopsy 3 2, but usually 3 3.
Gleason grade 4 and 3 in a punch biopsy. HE- sectional
Gleason grade 5 in a punch biopsy. HE- sectional
Significance of Gleason score
The Gleason score is next to the TNM classification and the PSA level is the most important prognostic factor in prostate cancer (see also the main article prostate cancer).
A Gleason score of 2 to 4 for well-differentiated tumors (grade 1 according to TNM ), a score 5-6 describes moderately differentiated tumors ( grade 2 according to TNM ), a score of 7 is moderate to poorly differentiated (grade 2 -3 according to TNM ) and a score 8-10 for poorly - up dedifferentiated tumors (grade 3 according to TNM ).
Tumors having a Gleason score of 2-4 are generally randomly in a prostate operation discovered (eg Ausschälungen in a BPH), while most of the tumors are found in the context of the biopsy examination, a score of 6 or 7 have. Tumors with a score of 8 to 10 are often fast growing aggressive tumors that have progressed at the time of diagnosis often.
One way to obtain additional information on the cancer cells, in particular in good differentiation that provides DNA cytometry.