The document discusses screening and active surveillance for prostate cancer. It summarizes that screening with PSA testing can reduce prostate cancer mortality by 20% but also leads to overdiagnosis of indolent cancers. Active surveillance is presented as an alternative to immediate treatment for selected low-risk prostate cancer patients with criteria such as Gleason score ≤6, PSA<10ng/ml, and limited cancer in biopsy cores. Studies found that 29-50% of patients identified by screening as low-risk were found to have more aggressive cancer upon undergoing radical prostatectomy.