Gleason Score (Detail)

A subjective method of measuring the differentiation of cells to classify tumors by their microscopic appearance and how aggressively the cancer cells may multiply. This system divides prostate cancer into five histological patterns ranging from 1-5. Patterns 1 and 2 represent well- differentiated tumors and are dealt with more easily; Gleason patterns 3 represents moderately well-differentiated tumor cells beginning to scatter; Gleason patterns 4 and 5 indicate poorly differentiated cells with the potential for fast growth. The total Gleason score is determined by adding a primary and secondary score pattern for each prostatic lesion i.e. 3+4=7. The most well-differentiated cancer cells would consist entirely of Gleason pattern 1 ( primary +secondary + 1+1 or Gleason 2 ) and the most poorly differentiated cancer cells would have a 5+5 or total Gleason score of 10.