Monitoring prostate cancer: Imaging-guided biopsies examined

This study evaluated recent evidence comparing standard systematic biopsies to imaging-guided biopsies in measuring prostate cancer growth.

While there was no clear advantage of imaging-guided biopsies over standard systematic biopsies, researchers concluded that a combination of the two techniques provides the highest accuracy.

The standard way to reliably monitor and grade prostate cancer involves taking regular biopsies (tissue samples) from the prostate. Biopsies are typically done blindly, by systematically taking 10 to 12 separate tissue samples from different locations on the prostate gland. Recently, it has been suggested that targeted biopsies, guided by imaging techniques that provide visual representations of the prostate gland, can be more accurate than standard systematic biopsies. Imaging techniques used to assist biopsies include multiparametric magnetic resonance imaging (mpMRI) and ultrasound-based techniques such as elastography (measures whether tissue is hard or soft), contrast-enhanced ultrasound, and histoscanning (images changes in tissue). The accuracy of a biopsy technique is usually measured by its sensitivity to detect prostate cancer. The aim of this review was to compare various imaging-guided biopsy techniques in the detection of prostate cancer.

This analysis included 28 studies, involving a combined total of 7,425 men undergoing testing for prostate cancer. Detection accuracy of prostate cancer using targeted biopsies (guided by different imaging techniques) were compared to those of standard systematic biopsies.

A total of 15 studies included in the review examined mpMRI-targeted biopsies. 5 trials noted higher detection rates for mpMRI-targeted biopsies compared to standard systematic biopsies. 8 trials noted roughly equal detections rates for both techniques. However, nearly all of the studies reviewed (14 of the 15 studies) reported a significant increase in prostate cancer detection rates when the two techniques were combined. On average, the detection rate was around 25% higher when mpMRI was combined with standard systematic biopsies, when compared to standard systematic biopsies alone.

Elastography-targeted biopsies were investigated in 5 studies. Of these, 2 studies noted an advantage in detection rates of elastography-targeted biopsies over standard systematic biopsies. 2 other studies, however, noted higher detection rates with standard systematic biopsies. All studies showed increased accuracy in detecting prostate cancer when the two techniques were combined.

6 studies investigated contrast-enhanced ultrasound-targeted biopsies. Only one study noted an advantage with this technique over standard systematic biopsies alone. The other 5 studies showed with contrast-enhanced ultrasound-targeted biopsies an equal or lower prostate cancer detection rate than with standard systematic biopsies. All studies noted increased accuracy when combining the two biopsy techniques in the detection of prostate cancer.

2 studies compared histoscanning-targeted biopsies with standard systematic biopsies. While one study showed a lower detection rate for histoscanning-targeted biopsies (38%) than for standard systematic biopsies (63%), the other study noted approximately equal detection rates for both techniques (28 and 29%). Combining the two biopsy techniques was found to be beneficial in one study, but not in the other.

This large review concluded that there is no clear advantage of imaging-guided biopsy techniques over standard systematic biopsies in measuring prostate cancer. However, the combination of systematic and targeted biopsies is associated with the highest level of accuracy.