Unexpectedly high variability in determining tumour extent in prostatic biopsies: implications for active...

Area of Science:

• Uropathology
• Oncology
• Medical Diagnostics

Background:

• Prostate cancer tumour content in biopsies is crucial for determining cancer volume and patient prognosis.
• Current guidelines recommend reporting tumour content as a percentage or linear length (mm).

Purpose of the Study:

• To investigate current practices for reporting prostate cancer tumour content in biopsies.
• To assess interobserver variability among pathologists in diagnosing prostate cancer biopsy cases.

Main Methods:

• A web-based survey collected data from 304 pathologists on their reporting practices.
• Analysis of 10 standard prostate cancer biopsy cases using virtual microscopy.
• Evaluation of self-reported tumour extent measures and interobserver agreement.

Main Results:

• Most pathologists reported tumour extent using percentages (43.4%) or a combination of percentages and mm (37.6%).
• Significant interobserver variability was observed, particularly when using percentages.
• Methods for determining percentages varied widely, contributing to inconsistent results.

Conclusions:

• High interobserver variability exists in reporting prostate cancer tumour content in biopsies.
• This variability is particularly concerning for patients eligible for active surveillance.
• Reporting absolute tumour measurements demonstrates lower variability compared to percentages.