The literature can be confusing about differences in the grading based on whether it’s a radical prostatectomy or TRUS biopsy and whether to go with the most common or the highest grade and the use of a tertiary grade.
This appears to be the current approach where I work:
- Grading for transrectal ultrasound guided biopsies and radical prostatectomies are the same
- The most prevalent and second most prevalent grade are added up (eg: 3+4, 4+3 however there does not appear to be a clinical difference in how these are managed)
- The tumour needs to show at least 5% of a grade of tumour to for it to be included in the grading including the tertiary grade
- The tertiary grade should be used only rarely. When all 3 grades are present. Then the most prevalent and the highest grade is used with the remaining going into the tertiary. (eg: 3+5=8 with tertiary 4 when all 3 present equally in a core bx)
- More likely to have a tertiary grade in a prostatectomy as you see much more prostatic tissue.
- Grade 3 well formed glands you can draw around, Grade 4 when cribriform or fused glands, Grade 5 when single glands, solid areas or glands associated with comedo type necrosis
RCPath dataset for reporting prostatic carcinoma.