Inter-observer variability of cribriform architecture and percent Gleason pattern 4 in prostate cancer: relation to clinical outcome

Abstract

The Grade group is an important parameter for clinical decision-making in prostate cancer. Recently, percent Gleason pattern 4 and presence of invasive cribriform and/or intraductal carcinoma (CR/IDC) have been recognized for their independent predictive value for prostate cancer outcome. There is sparse data on the inter-observer agreement for these pathologic features in practice. Our objectives were to investigate inter-observer variability of percent Gleason pattern and CR/IDC and to relate individual tumour scores to clinical outcome. Our cohort included 80 consecutive radical prostatectomies with a median follow-up 87.1 months (interquartile range 43.3-119.2), of which the slide with largest tumour volume was scored by six pathologists for Grade group (four tiers: 1, 2, 3 and 4/5), percent Gleason pattern 4 (four tiers: 0-25%, 26-50%, 51-75% and 76-100%) and presence of CR/IDC (two tiers: absent, present). The individual assignments were related to post-operative biochemical recurrence (20/80). Inter-observer agreement was substantial (Krippendorff's α 0.626) for assessment of Grade group and moderate for CR/IDC (α 0.507) and percent Gleason pattern 4 (α 0.551). For each individual pathologist, biochemical recurrence rates incremented by Grade group and presence of CR/IDC, although such relation was less clear for percent Gleason pattern 4. In conclusion, inter-observer agreement for CR/IDC and percent Gleason pattern 4 is lower than for Grade groups, indicating awareness of these features needs further improvement. Grade group and CR/IDC, but not percent Gleason pattern 4 was related to biochemical recurrence for each pathologist, indicating overall validity of individual grade assignments despite inter-observer variability.

Predicting biochemical recurrence of prostate cancer with artificial intelligence

“…There have been improvements to prostate cancer grading 11 , 13 , and recently the cribriform pattern is suggested to be important for prognostics 14 , 43 . However, the evaluation of this pattern can show a range of inter-observer variability 44 , although a recent consensus approach could help decrease this variability 45 . Although we certainly have to keep in mind all the before-mentioned limitations, our findings are in line with outcomes concerning adverse behaviour in earlier work.…”

Grade migration and important prognostic factors in a pathology specimen for radical radiotherapy in prostate cancer patients

“…This factor was the only one which was significant (marginally) in the present study, but it did not translate into bDFS. Factors other than the Gleason score, such as cribriform pattern and/ or intraductal carcinoma or perineural invasion, may have an impact on treatment outcome [23,24,25]. According to contemporary rules, these should also be enclosed in a pathology report [26].…”

Cribriform architecture outperforms Gleason pattern 4 percentage and tertiary Gleason pattern 5 in predicting the outcome of Grade Group 2 prostate cancer patients

“… 19 , 20 In an interobserver study of 80 RP slides, the reproducibility of assigning TP5 was lower than those of IC/IDC and the GP4 percentage. 21 As far as we know, no specific interobserver studies have yet been performed on tertiary patterns. We hypothesise that the reproducibility of assigning TP5 is low because it can be overlooked or interpreted as poorly formed GP4.…”