Trends in disagreement with outside genitourinary pathology diagnoses at an academic center

Abstract

Aims: To evaluate the frequencies and types of disagreements in a contemporary urological second-opinion consult service in order to improve pathologist awareness.

Methods: For 7 years ending 30 October 2021, records were kept of our department's total urologic outside consultation and disagreed-upon cases. Disagreements were categorized according to specimen type and nature of conflict. All grading and staging assignments used International Society of Urological Pathology (ISUP) criteria. Statistical analyses for each specimen type included the percent disagreement. Cohen's kappa analysis was done to measure interrater reliability on the prostate biopsies, prostatectomies, and the bladder biopsies/resections. In addition, for the prostate biopsies, the potential for change in treatment candidacy calculation (CTC), was assessed as sum of changes from cancer to non-malignant tissue or the reverse, plus changes from Gleason Grade group (GG)1 to GG ≥ 2 (3 +4 =7) or the reverse.

Results: Overall mean disagreement rate for all specimens was 15.2%. The highest rate was among 1545 prostate biopsy cases, where 410 contained disagreements (26.5%). 118 (7.6%) met criteria for CTC: 10 cases were altered from cancer to non-cancer, 38 cases downgraded from GG≥ 2 to GG1, and 70 upgraded from GG1 to GG≥ 2. Second opinion downgraded the overall highest GG more often than it upgraded it, with downgrade:upgrade ratios of 64:37 for the GG1/GG2 threshold, 79:67 for the GG2/GG3, and 14:0 for the GG3/GG4. 146 specimen parts had disagreements as to cancer vs. suspicious vs. benign, with 85 undercalled and 61 overcalled. Other rates of disagreement included: prostatectomy 34/198 (17.2%); bladder resection or biopsy 68/591 (11.5%); kidney 27/175 (15.4%); and orchiectomy 9/82 (11.0%). In bladder specimens, overgrading was 6X more frequent than undergrading; and overstaging muscularis propria invasion was 6X more frequent than understaging.

Conclusions: The review of uropathologic materials before definitive therapy can lead to changes that impact clinical decisions significantly. As an example, for prostate biopsies, candidacy for active surveillance versus definitive treatment hinges on GG1 versus 2 and this distinction constituted most CTC cases. The above findings highlight aspects of urological pathology to be emphasized to residents in training, and pathologists in practice.

Keywords: Concordance; Disagreement; Genitourinary pathology; Grading; Prostate; Second opinion.