Imaging modalities in focal therapy: patient selection, treatment guidance, and follow-up

Focal therapy for prostate cancer is emerging as a management option between active surveillance and radical treatments. In this article, we present two of the most important imaging modalities in focal therapy, multiparametric MRI (mpMRI) and ultrasonography. We review the recent advances within these two platforms.

State-of-the-art imaging in all phases of focal therapy is essential for treatment safety. In patient selection, treatment guidance, and follow-up, different aspects of imaging are important. mpMRI is an imaging technology with high imaging resolution and contrast. This makes it an excellent technology for patient selection and treatment planning and follow-up. Ultrasound has the unique property of real-time image acquisition. This makes it an excellent technology for real-time treatment guidance. There are multiple novelties in these two platforms that have increased the accuracy considerably. Examples in ultrasound are contrast-enhanced ultrasonography, elastography, shear-wave elastography, and histoscanning. In mpMRI, these advantages consist of multiple sequences combined to one image and magnetic resonance thermometry.

Standardization of multiparametric transrectal ultrasound and mpMRI is of paramount importance. For targeted treatment and follow-up, a good negative predictive value of the test is important. There is much to gain from both of these developing fields and imaging accuracy of the two platforms is comparable. Standardization in conduct and interpretation, three-dimensional reconstruction, and fusion of the two platforms can make focal therapy the standard of care for prostate cancer.