title: Defining 'progression' and triggers for curative intervention during active surveillance.
abstract: OBJECTIVE
  Low-risk and many cases of low-intermediate risk prostate cancer have little or no metastatic potential, and do not pose a threat to the patient in his lifetime. Substantial recent evidence, reviewed in this article, has clarified who these patients are and supports the use of conservative management in such individuals.
  
  
  RESULTS
  A key element of conservative management is the early identification of those 'low-risk' patients who harbour higher risk disease and benefit from definitive therapy. This represents about 30% of newly diagnosed low-risk patients. A further small proportion of patients with low-risk disease demonstrates true biological progression over time to higher grade disease (as distinct from grade increase on repeat biopsy due to resampling). Men with lower risk disease can defer treatment, in most cases for life. The results of active surveillance, embodying conservative management with selective delayed intervention for the subset who are reclassified as higher risk over time based on repeat biopsy, imaging or biomarker results, are associated with a 5% cancer-specific mortality at 15 years.
  
  
  CONCLUSIONS
  Active surveillance for low-risk prostate cancer is well tolerated in the intermediate-long term time frame. Further refinement of the surveillance approach is ongoing, incorporating MRI, targeted biopsies and molecular biomarkers to improve appropriate patient selection and triggers for intervention.
authors.affiliation: Division of Urology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Laurence
authors.initials: L
authors.lastname: Klotz
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood; D001706:Biopsy; D018450:Disease Progression; D006801:Humans; D008297:Male; D018579:Patient Selection; D011467:Prostate / Q000473:pathology*; D017430:Prostate-Specific Antigen / Q000097:blood*; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology* / Q000628:therapy; D018570:Risk Assessment; D013997:Time Factors; D057832:Watchful Waiting
chemical_list: D014408:Biomarkers, Tumor; D017430:Prostate-Specific Antigen