title: What tumours should we treat with focal therapy based on risk category, grade, size and location?
abstract: OBJECTIVE
  Focal therapy aims to reduce side-effects of active whole-gland therapies with an acceptable or noninferior oncologic benefit for the patient. The definition of the lesion to treat using this tissue-preserving approach is central, and there is a recent shift in considering more aggressive disease than in the past. This article examines recent consensus reports, assessment of emerging techniques, histologic considerations as well as results of trials and their development.
  
  
  RESULTS
  Accumulation of evidence reinforces the concept of clinically significant disease. Latest histologic assessment studies specify the index lesion characteristics. Index lesion localization was accurately evaluated by both multiparametric MRI (mpMRI)-targeted and transperineal mapping biopsy techniques against reference standard. mpMRI continues its development in accurate disease stratification. Development of new treatment modalities allows the clinician to investigate treatment of a lesion in various zonal anatomy locations. Consensus reports establish the intermediate risk population as the target for focal therapy, leaving very low risk disease to surveillance. Reviews of past clinical trials, including intermediate risk population, reveal encouraging oncologic follow-up. Ongoing trials will test focal therapy of index lesion with surveillance of insignificant secondary lesions.
  
  
  CONCLUSIONS
  Focal therapy should be investigated for intermediate risk population, leaving very low risk to surveillance. Detection and stratification techniques, namely mpMRI-targeted and transperineal biopsies, have an evolving role in lesion selection to confirm encouraging oncologic benefit for the patient.
authors.affiliation: aResearch Department of Urology, Division of Surgery and Interventional Science, University College London bProstate Unit, Department of Urology, University College London Hospitals NHS Foundation Trust, London, UK.
authors.forename: Clement
authors.initials: C
authors.lastname: Orczyk
authors.forename: Mark
authors.initials: M
authors.lastname: Emberton
authors.forename: Hashim U
authors.initials: HU
authors.lastname: Ahmed
mesh_terms: D006801:Humans; D061705:Image-Guided Biopsy; D053783:Magnetic Resonance Imaging, Interventional; D008297:Male; D060787:Neoplasm Grading; D059351:Organ Sparing Treatments / Q000379:methods*; D018579:Patient Selection; D017410:Practice Guidelines as Topic; D011471:Prostatic Neoplasms / Q000401:mortality / Q000473:pathology / Q000628:therapy*; D012015:Reference Standards; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D018084:Ultrasonography, Interventional; D036761:Ultrasound, High-Intensity Focused, Transrectal