A grading dilemma; Gleason scoring system: Are we sufficiently compatible? A multi center study

Area of Science:

• Uropathology
• Prostate Cancer Diagnosis
• Histopathology

Background:

• Gleason scoring is crucial for prostate cancer prognosis.
• Interobserver variability in Gleason scoring can affect patient outcomes.
• Existing definitions of Gleason patterns may require updates.

Purpose of the Study:

• To assess interobserver agreement among general pathologists and an expert uropathologist.
• To quantify variability in Gleason scoring across different centers.
• To identify potential issues in current prostate cancer grading practices.

Main Methods:

• Review of 50 H&E stained prostate cancer slides by 8 pathologists from 6 centers.
• Comparison of Gleason scores using Fleiss' and Cohen's kappa tests.
• Analysis of agreement based on pathologist experience and center affiliation.

Main Results:

• Fleiss' kappa indicated moderate agreement for primary Gleason pattern (0.54) and total Gleason score (0.44).
• Agreement for the Gleason grade grouping system was also moderate (kappa=0.45).
• Variability was observed among general pathologists with differing experience levels.

Conclusions:

• Moderate interobserver agreement in Gleason scoring poses challenges for consistent prostate cancer grading.
• Despite well-defined patterns, variability in scoring persists.
• This variability can complicate accurate prognosis and treatment decisions.