Consistent with this notion, recent phase II clinical trials have reported ≥95% 5-7 year PSA relapse-free survival (bRFS) with low toxicity rates in prostate cancer patients with NCCN low-risk and favorable intermediated-risk (FIR) disease treated with 5-fraction regimens of 35-40 Gy stereotactic ablative radiotherapy (SABR) (15–17). This evidence concerns the gene KLK3 and prostate cancer.