Diagnostic uncertainty expressed in prostate needle biopsies - A College of American Pathologists Q-Probes study of 15 753 prostate needle biopsies in 332 institutions

Objective.-To determine the rate of diagnostic uncertainty in rendering dia gnoses on prostate needle biopsies and to examine pathology practice variab les that influence that rate. Design.-Anatomic pathology departments participating in the College of Amer ican Pathologists Q-Probes laboratory quality improvement program retrospec tively reviewed their last 50 consecutive prostate needle biopsy diagnoses. For each diagnosis, participants provided information concerning patients' prostate-specific antigen levels; number, locations, and laterality of bio psy specimens; number of tissue levels examined; performance of high-molecu lar-weight cytokeratin immunoperooxidase staining; and acquisition of consu ltations from general pathologists or experts in prostate pathology. Charac teristics of pathology practices included yearly surgical and prostate need le biopsy caseloads, number of pathologists rendering biopsy diagnoses, use of standard descriptive checklists, access to patients' prostate-specific antigen and digital rectal examination results, percentages of prostate nee dle biopsies routinely submitted for internal consultations, and presence o f departmental experts in prostate pathology. Setting and Participants.-Three hundred thirty-two public and private insti tutions located in the United States (n = 318), Canada (n = 6), Australia ( n = 5), United Kingdom (n = 2), and Guam (n = 1). Main Outcome Measure.-The rate of diagnostic uncertainty in prostate needle biopsy diagnoses. Results.-Participants submitted diagnoses on a total of 15 753 prostate nee dle biopsy cases, of which 33.4% were adenocarcinoma; 55.5% were benign; 3. 9% were carcinoma in situ, prostatic intraepithelial neoplasia, or both; an d 7.1% were diagnostically uncertain. The median rate of diagnostic uncerta inty was 6%, ranging from 0 at the 10th percentile to 14% at the 90th perce ntile of all participating laboratories. Performing high-molecular-weight c ytokeratin immunoperoxidase staining resolved diagnostic uncertainty in 68% of cases in which it was performed, and obtaining intradepartmental and ex tradepartmental consultations resolved diagnostic uncertainty in 70% to 87% of cases for which they were obtained. Knowledge of patients' prostate-spe cific antigen results and examining multiple biopsy cores had marginal effe cts on the rate of uncertainty. Thoroughness of prostate gland sampling and examination of multiple tissue block levels were not associated with the a ggregate rate of diagnostic uncertainty. We found no particular pathology d epartmental practices or institutional demographic characteristics associat ed with institutional rates of diagnostic uncertainty. Conclusions.-Use of high-molecular-weight cytokeratin immunoperoxidase stai ning and obtaining intradepartmental and extradepartmental consultations ma y be effective in reducing diagnostic uncertainty in prostate biopsies.