Pooled data analysis performed recently demonstrated good oncologic outcomes with salvage treatment-free survival rate as high as 98% at a mid-term follow-up. Continence and potency rates after HIFU focal therapy were extremely favorable in our pooled data analysis, making this a promising technique in the years to come. However, many points need to be addressed in order to move beyond the proof of concept.
The first and most important point at our view is the understanding of the molecular biology of the index lesion. Prostate cancer is a multifocal disease with different lesions harboring different malignant potentials. We think that genetic characterization of the indolent disease is paramount. Efforts should be made to clarify these points. The second most important issue is to detect on imaging all aggressive lesions that should be treated and to understand the limitations of multiparametric MRI. Small foci of aggressive disease and cribriform type are frequently missed by multiparametric MRI. Results of studies evaluating the accuracy of PET/MRI to detect aggressive disease missed by MRI alone are eagerly awaited. Third, in bore and elastic fusion software targeted biopsies offer good quality control and higher detection rate but still significant numbers of patients with a significant disease are missed. Of note, the most advanced software allows triple elastic fusion between PET imaging, mpMRI and 3D ultrasound. Future studies will show us if higher detection rates of significant prostate cancer are obtained. Fourth, the cartography-based quality control is a necessary ground to target focal therapy. The lesion to be treated should be well visualized and the effect of treatment should be well monitored. The margin of treatment should be elaborated based on the size of the lesion to treat and the grade.
At present, a good proportion of patients treated with focal therapy are also candidates for active surveillance. Patients refusing or unfit for radical treatment represent the other proportion, making focal therapy an exception treatment. Experts performing focal therapy should work together to establish an international registry and a standardized follow-up. This will allow a prospective registration of the clinical and pathological characteristics of included patients and their long-term follow-up. Patients should be monitored carefully to detect early recurrence and to manage accordingly. If all of these points are well addressed, we think that the future of focal therapy will be bright and focal therapy will become the rule instead of the exception.
Written by: Fouad Aoun, MD, MSc, FEBU, department of Urology, Jules Bordet Institute, Brussels, Belgium
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