The role of magnetic resonance imaging in targeting prostate cancer in patients with previous negative biopsies and elevated prostate-specific antigen levels.

摘要

Lawrentschuk and Fleshner [1] are to be congratulated on their editorial, which makes the argument for increased research into the role of MRI in the detection of prostate cancer [2] and its potential to guide treatment such as focal therapy [3]. There are several important issues to which we would like to draw attention, (i) Reports on MRI are limited due to the use of either inaccurate or inappropriate reference standards.Transrectal biopsies are inherently inaccurate; they miss cancer in 20-30% of men who have a negative biopsy and they under-sample most areas, but in particular the apex, transition zone and anterior horns of the peripheral zone. The use of radical prostatectomy whole-mount specimens as a reference standard introduces a selection or evaluation bias, as men with low-risk disease, or unfit for surgery, and those with no cancer are not evaluated. We propose that the reference standard to evaluate any imaging method in men with a clinical suspicion of prostate cancer is template transperineal prostate-mapping biopsies, sampling the gland every 5 mm. This has been shown to have a 95% accuracy in detecting clinically significant cancer [4,5l.