Men diagnosed with low-risk, or Gleason 6, prostate cancer are often prescribed frequent monitoring, termed active surveillance or ‘watchful waiting,’ as opposed to being aggressively treated. Two leading scientists debate the benefits of the practice: Dr. Laurence Klotz, from Sunnybrook Health Sciences Centre in Canada, says active surveillance ensures that patients aren’t misdiagnosed with low-risk prostate cancer when they actually have a higher-risk form of the disease, a mistake that occurs in 25% of patients. Active surveillance also allows clinicians to monitor patients for progression of prostate cancer and, most importantly, it reduces the rate of overtreatment of low-risk prostate cancer types, thereby reducing the risk of treatment complications. Dr. Oliver Sartor, a urologist from Tulane University School of Medicine, contends that the practice of active surveillance is not well defined and too complicated. It involves repeated testing and procedures and is not widely accepted or practiced by community urologists. He outlines two clinical studies that show no benefit of active surveillance on long-term survival, and suggests that patients with low-risk prostate cancer may be better served by simply treating their symptoms.