Gleason Grading System - Primary, Secondary, and Tertiary

Primary, Secondary, and Tertiary

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 grades 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 debatable as to what the full extent the tertiary component has on the aggressiveness of a cancer.