Histopathological re-evaluations of biopsies in prostate cancer: a nationwide observational study

Grading prostate biopsies has an important role in determining treatment strategy. Histopathological evaluations suffer from interobserver variability and therefore biopsies may be re-evaluated.

To provide insight into the extent of, characteristics associated with and clinical implications of prostate biopsy re-evaluations in daily clinical practice.

Patients diagnosed with prostate cancer (PCa) by biopsy between October 2015 and April 2016 identified through the Netherlands Cancer Registry were included. The proportion of re-evaluations was assessed and characteristics were compared between patients with and without biopsy re-evaluation. Interobserver concordance of ISUP grade and EAU prognostic risk classification was determined by calculating Cohen's kappa.

Biopsy re-evaluation was performed in 172 (3.3%) of 5214 patients. Primary reason for re-evaluation in patients treated with curative intent was referral to another hospital. Most referred patients treated with curative intent (n = 1856) had no re-evaluation (93.0%, n = 1727). Patients with biopsy re-evaluation were younger and underwent more often prostatectomy compared to patients without re-evaluation. The disagreement rate for ISUP grade was 26.1% and interobserver concordance was substantial (κ-weighted = 0.74). Re-evaluation resulted in 21.1% (n = 14) of patients with localised PCa in a different prognostic risk group. More tumours were downgraded (57.1%) than upgraded (42.9%). Interobserver concordance was very good (κ _weighted = 0.85).

Pathology review of prostate biopsies is infrequently requested by clinicians in the Netherlands but in a non-negligible minority of patients with localised PCa the pathology review led to a change in prognostic risk group which might impact their treatment.