PATHOLOGY

Current practice of Gleason grading among genitourinary pathologists
Egevad L, Allsbrook WC Jr, Epstein JI
Department of Pathology and Cytology, Karolinska Hospital, Stockholm, Sweden
Hum Pathol. 2005; 36 (1): 5-9

• There is consensus that the Gleason system should be used for grading of prostate cancer. However, a number of controversial issues remain as regards how this grading is applied. A questionnaire was sent to 91 genitourinary pathologists in countries around the world with the purpose to survey current practice of Gleason grading. The response rate was 74%, including 43 North American pathologists and 24 from other continents. Of all participants, only 13% and 36%, respectively, ever diagnosed a Gleason score (GS) of 2 to 3 or 4 on needle biopsies (NBX), and 88% of those who did so assigned a GS 4 to < 1% of cancers. Cribriform Gleason pattern (GP) 3 was acknowledged by 88% but a majority of them would classify < or =20% of cribriform patterns as GP 3. One third only accepted cribriform or fusion patterns as GP 4, but two thirds also included incomplete or poorly defined glands. For GP 5 to be identified on NBX, 83% required clusters of individual cells, strands, or nests seen at less than x40 lens magnification. Only 26% defined GS on NBX as primary + tertiary GP, and a majority would mention a tertiary pattern separately. For NBX, global or highest GS was reported by 40% and 10%, respectively, whereas 46% only gave a separate GS for each individual NBX core. In conclusion, there is a need to standardize practical application of Gleason grading both in terms of interpretation of patterns as well as how grading is reported. Our survey data provide information to general pathologists about the most common grading practices among genitourinary pathologists.
  
  
• Editorial Comment
  The questionnaire clearly disclosed controversies among pathologists regarding how to report Gleason grading. During the annual meeting of the United States and Canadian Academy of Pathology (USCAP) held in San Antonio, Texas, 2005, a consensus meeting on Gleason grading was organized by JI Epstein. Over 70 urological pathologists were invited to attend and the result of the meeting shall be published in the American Journal of Surgical Pathology. Three recommendations are particularly useful for the urologist:
  a) Gleason score 4 rarely is seen on needle biopsies and almost never the lesion is seen in its totality due to the thickness of the core, therefore, a note should be added to the report stating that the Gleason score probably is underestimated;
  b) in case a tertiary grade is present on needle biopsies, the consensus of the group was to report the primary pattern and the highest grade as the secondary pattern. Example: grade 3 (60% of the area), grade 4 (30% of the area), grade 5 (10% of the area) - Gleason 3 + 5 = 8;
  c) each core should be graded individually; the urologist should consider the highest score.

Dr. Athanase Billis
Full-Professor of Pathology
State University of Campinas, Unicamp
Campinas, São Paulo, Brazil