MRI-targeted biopsy: is systematic biopsy obsolete?

Introduction: Although prostate cancer is the most common non-cutaneous cancer in men, it is traditionally diagnosed with a non-targeted, systematic transrectal ultrasound prostate biopsy (TRUS-Bx). This technique has been demonstrated to both under-detect clinically significant (CS) cancer and over-detect clinically insignificant cancer, and performs poorly in patients with a prior negative biopsy. With recent advances in MRI technology, most prominently the advent of multiparametric MRI, MRI-targeted prostate biopsy (MRI-TB) has been gaining favor as a more accurate alternative to TRUS-Bx. In this review, we attempt to summarize the current literature on MRI-TB and to determine if there is evidence supporting the use of MRI-TB alone. Materials and methods: The literature was reviewed for articles pertaining to MRI-TB and its performance compared to systematic biopsy. Results: Most studies support the increased sensitivity of MRI-TB (0.90, 95% CI 0.85-0.94) compared to TRUS-Bx (0.79, 95% CI 0.68-0.87) for the detection of CS prostate cancer, as MRI-TB can detect up to 30% more high risk and 17% fewer low risk cancers. MRI-TB also tends to perform better than TRUS-Bx in patients with prior negative biopsy, as TRUS-Bx may miss up to half of CS cancers detected by MRI-TB, and in those with lesions at atypical locations. However, as the technology for imaging and image-guided biopsies continues to develop, there is still a role for TRUS-Bx in the management of patients with prostate cancer. Conclusions: Our analysis of the literature suggests that although MRI-TB is superior to TRUS-Bx, there is still a role for traditional systematic biopsy.