Clinical Report: Nationwide Evaluation of Targeted and Combination Prostate Biopsies in Denmark
Overview
This nationwide Danish study (2012–2016) assessed the diagnostic accuracy and clinical outcomes of combination biopsies (cBx) compared to targeted (tBx) and systematic biopsies (sBx) alone. Combination biopsies demonstrated higher concordance with radical prostatectomy pathology and provided improved risk stratification for prostate cancer-specific mortality.
Background
Magnetic resonance imaging (MRI) has revolutionized prostate cancer diagnosis by enabling targeted biopsies (tBx), which focus on suspicious lesions, potentially reducing unnecessary biopsies. However, concerns exist regarding overgrading and overtreatment with tBx alone. Combining targeted and systematic biopsies (cBx) has been proposed to enhance detection of clinically significant prostate cancer. Prior to this study, the nationwide impact of implementing cBx was unknown.
Data Highlights
Biopsy Strategy
Number of Men
Prostate Cancer Diagnosis Rate (%)
Concordance with RP (Weighted Kappa)
Unchanged Gleason Grade (%)
Upgrading (%)
Downgrading (%)
6-year Prostate Cancer-specific Death (%) for GG 2
6-year Prostate Cancer-specific Death (%) for GG 3
6-year Prostate Cancer-specific Death (%) for GG 4
6-year Prostate Cancer-specific Death (%) for GG 5
Combination Biopsy (cBx)
590
67
0.53 (weak)
54
25
21
1.5
6.8
3.8
22
Targeted Biopsy (tBx) component of cBx
590
67
0.38 (minimal)
45
42
13
4.2
4.7
5.0
30
Systematic Biopsy (sBx) component of cBx
590
67
0.16 (none)
49
38
13
2.1
9.9
10
19
Standalone Systematic Biopsy (sBx)
29,815
67
0.29 (minimal)
54
33
16
NA
NA
NA
NA
Key Findings
Combination biopsy (cBx) showed the highest concordance with radical prostatectomy Gleason grading (weighted kappa 0.53), outperforming targeted (0.38) and systematic biopsies (0.16) alone.
54% of cBx cases had unchanged Gleason grade compared to prostatectomy, with 25% upgrading and 21% downgrading, indicating improved accuracy.
Standalone systematic biopsies had minimal concordance (0.29) and similar rates of unchanged Gleason grade (54%) but higher upgrading (33%) and lower downgrading (16%) compared to cBx.
Prostate cancer-specific mortality at 6 years was 0% for non-malignant and Gleason grade 1 across all biopsy methods.
For Gleason grade 2, cBx showed the lowest 6-year prostate cancer-specific death (1.5%) compared to tBx (4.2%) and sBx (2.1%), suggesting better risk stratification.
Higher Gleason grades (4 and 5) diagnosed by cBx were associated with lower or comparable prostate cancer-specific mortality compared to tBx and sBx.
Clinical Implications
The findings support the use of combination biopsy (cBx) incorporating both targeted and systematic sampling to improve diagnostic accuracy and risk stratification in prostate cancer evaluation. Implementing cBx may reduce misclassification and better guide treatment decisions, potentially minimizing overtreatment. Clinicians should consider cBx as a standard approach in men undergoing initial prostate biopsy, especially in settings with access to MRI.
Conclusion
Nationwide data from Denmark demonstrate that combination biopsy improves concordance with definitive pathology and provides superior prognostic information compared to targeted or systematic biopsy alone. This supports broader adoption of combination biopsy strategies in prostate cancer diagnosis.
References
Danish Prostate Cancer Registry 2 (DaPCaR2) -- Nationwide prostate biopsy data 2012-2016
MRI and prostate biopsy techniques -- Clinical context and prior studies
