Context: It remains unclear whether patients with suspicion of prostate cancer (PCa) and negative multiparametric magnetic resonance imaging (mpMRI) can safely obviate prostate biopsy.
Objective: To systematically review the literature assessing the negative predictive value (NPV) of mpMRI in patients with suspicion of PCa.
Evidence acquisition: The Embase, Medline and Cochrane databases were searched up to February 2016. Studies reporting pre-biopsy mpMRI results using transrectal or transperineal biopsy as reference standard were included. We further selected for meta-analysis studies with at least 10-core biopsies as reference standard, mpMRI comprising at least T2-weighted and diffusion-weighted imaging, positive mpMRI defined as a PI-RADS/Likert score of ≥3/5 or ≥4/5, results reported at patient level for detection of overall PCa or clinically significant PCa (csPCa) defined as Gleason ≥7 cancer.
Evidence synthesis: 48 studies (9613 patients) were eligible for inclusion. At patient level, median prevalence was 50.4% (IQR, 36.4-57.7%) for overall cancer and 32.9% (IQR, 28.1-37.2%) for csPCa. Median mpMRI NPV was 82.4% (IQR, 69.0-92.4%) for overall cancer and 88.1% (IQR, 85.7-92.3) for csPCa. NPV significantly decreased when cancer prevalence increased, for overall cancer (r=-0.64, p<0.0001) and csPCa (r=-0.75, p=0.032). Eight studies fulfilled the inclusion criteria for meta-analysis. Seven reported results for overall PCa. When the overall PCa prevalence increased from 30% to 60%, the combined NPV estimates decreased from 88% (95% confidence interval (95% CI), 77–99%) to 67% (95% CI, 56–79%) for a cut-off score of 3/5. Only one study selected for meta-analysis reported results for Gleason ≥7 cancers, with a positive biopsy rate of 29.3%. The corresponding NPV for a cut-off score of ≥3/5 was 87.9%.
Conclusion: mpMRI NPV varied greatly depending on study design, cancer prevalence, and definitions of positive mpMRI and csPCa. Because cancer prevalence was highly variable among series, risk stratification of patients should be the initial step before considering prebiopsy mpMRI and defining those in whom biopsy may be omited when the mpMRI is negative.
Patient summary: This systematic review examined if multiparametric MRI scan can be used to reliably predict the absence of prostate cancer in patients suspected of having prostate cancer, thereby avoiding a prostate biopsy. The results suggest that whilst it is a promising tool, it is not accurate enough to replace prostate biopsy in such patients, mainly because its accuracy is variable and influenced by the prostate cancer risk. However, its performance can be enhanced if there were more accurate ways of determining the risk of having prostate cancer. When such tools are available, it should then be possible to use MRI scan to avoid biopsy in patients at low risk of prostate cancer.
- prostate cancer
- multiparametric magnetic resonance imaging
- prostate biopsy
- risk stratification