Active Surveillance Requires Follow-Up Being told you have prostate cancer does not always mean you need immediate treatment. In this clip, Geoffrey Sonn, MD, urologic oncologist at Stanford Medicine, explains why active surveillance is the preferred approach for many men with low-grade prostate cancer, and for select men with intermediate-grade disease. What is active surveillance? It means carefully monitoring prostate cancer over time using PSA tests, imaging, and follow-up visits rather than