Patients with stage pT2–3, N0, M0 prostate cancer, and undetectable PSA defined as ≤0.4 ng/ml with at least one adverse prognostic factor: positive surgical margins, ECE and/or SVI were randomized to receive ART with 60 Gy in 6 weeks to the prostate bed or observation. This evidence concerns the gene KLK3 and prostate cancer.