[Advances in the ultrasound diagnosis of prostate cancer]

Abstract

Objectives: Ultrasound guided biopsies are the mainstay in the diagnosis of prostate cancer. With the aim of improving diagnostic performances different protocols of prostate biopsy have been designed. The addition of vascular contrasts to the ultrasound allows for identification of hypervascular regions more likely to be cancer. The new ultrasound modalities enhance contrast signal and specifically differentiate its signal from the tissue reflections.

Method: A non structured review of the literature was conducted on the utility of the different ultrasound modalities and types in targeting the biopsies of the prostate.

Results: There are four types of ultrasound guided biopsies of the prostate: ultrasound guided biopsy of hypoechoic nodes, systematic biopsy protocols, Doppler guided biopsy and Contrast Enhanced Doppler guided biopsy. In spite of the broad literature only few series possess a methodologically correct design related to the use of reference standards. The diagnostic performance of each one of the different types of biopsy varies widely. Sensitivity and specificity of ultrasound guided biopsy of hypoechoic nodes depends on the type of population included in the study but in general its positive predictive value is low. The protocols of systematic biopsy increase the sensitivity of the prostate biopsy but still specificity is low. The Doppler techniques offer a marginal benefit. Contrast Enhanced Doppler guided biopsies series have reported only a slightly increase in sensitivity and a significant improvement of the odds risk for diagnostic of prostate cancer. New arising ultrasound modalities present with promising preliminary results.

Conclusions: Ultrasound guided biopsy have an acceptable sensitivity in the diagnosis of prostate cancer, however specificity is overall low. Among the different ultrasound techniques only Contrast Enhanced Ultrasound improves significantly the diagnostic risk of the biopsy although the sensitivity remains quite stable. New specific contrast ultrasound techniques are currently under investigation.