Saturation biopsies for prostate cancer: current uses and future prospects

Abstract

There is a trend towards increasing the number of cores sampled during ultrasound-guided prostate biopsy in an attempt to increase the likelihood of detecting malignancy. Here, the authors' analysis of current data indicates that this 'saturation' approach is best used to improve histological characterization of cancer, and for monitoring of men with a rising PSA level despite previous negative biopsy. Since its introduction, ultrasound-guided prostate biopsy has undergone significant evolution. Because of the low sensitivity of ultrasonography in detecting prostate cancer, tissue is sampled randomly within the gland. In an attempt to enhance cancer detection and characterization, the trend has been to increase the number of biopsy cores taken. Saturation biopsies of the prostate gland were first evaluated as a diagnostic tool. When performed as an initial procedure, saturation biopsies do not seem to improve cancer detection when compared to standard biopsy. However, saturation biopsies might be of clinical value in patients with previous negative standard biopsies but persistently rising PSA levels. As a staging tool, the use of saturation biopsies was proposed mainly to avoid overtreatment of clinically insignificant cancers. Results from clinical and autopsy studies have suggested that saturation biopsies are more accurate than standard biopsies in histological characterization of prostate cancer. Improving cancer characterization might require an increase in the number of cores taken, but knowing their precise location is paramount. Strict template guidance and three-dimensional techniques offer a more comprehensive approach than current ultrasound-guided approaches, and the advantage of precisely recording every core location. New imaging techniques, such as diffusion-weighted and spectroscopic MRI might also help in targeting prostate biopsies.