Combining visual-registration and image-fusion biopsy targeting strategies provide the highest rate of detecting clinically significant prostate cancers, according to results from the SmartTarget biopsy trial.

Multiparametric MRI improves the diagnostic sensitivity for clinically significant prostate cancer while reducing the overdetection of clinically insignificant cancer, but it remains unclear which MRI-targeted biopsy method is best. Dr. Hashim U. Ahmed of the Faculty of Medicine at University College London and colleagues sought to determine whether visual registration (mentally translating MRI targets onto real-time ultrasound images) is sufficient or whether it needs augmentation with image-fusion software.

Among 129 men who underwent both visual-registration and image-fusion biopsies, 93 (72%) had clinically significant prostate cancer (Gleason pattern of 3 or higher + 4 = 7) using both biopsy strategies. Each strategy alone detected 80 of these significant cancers, with each method identifying 13 diseases that the other missed so that the combination of the plans resulted in a 14% improvement in the detection of clinically significant prostate cancer.

Results were similar using an alternative definition of clinically significant prostate cancer (Gleason pattern of 4 or higher + 3 = 7), the researchers report in European Urology, online December 6. The safety profiles were similar with the two biopsy strategies, and there were no significant differences in patient-reported outcome scores.  "Both strategies missed clinically significant cancers detected by the other strategy and so should be used in combination to optimize cancer detection," the researchers conclude.

Cost-Benefit Analysis

"A cost-benefit analysis is a complex question beyond this study's scope," they add. "However, our results suggest potential benefits of a faster learning curve and higher repeatability that may enable less experienced centers to increase throughput and achieve cancer detection rates equivalent to those of highly experienced centers." Several of the authors report financial ties to SmartTarget Ltd., which is commercializing the image guidance device used in this study. 

This study, which directly compared transperineal image-fusion and visual-registration biopsy strategies, found no statistically significant difference in overall detection rates of clinically substantial PC. Both approaches missed clinically significant cancers detected by the other strategy and so should be used in combination to optimize cancer detection.The recent publication of the PROMIS trial [1] will increase demand from patients and policymakers to implement a mpMRI-based pathway given the degree of diagnostic superiority that was shown for this method compared with the standard of care.