KLK3 and Familial prostate cancer: Indeed, in aerobic exercise intervention trials spanning 12 weeks to 12 months during active surveillance for prostate cancer, prostate-specific antigen (PSA) was unchanged [42] or reduced modestly (CV 2.9–6.6%) [40, 41]– within the physiological variation for PSA (CV ~ 7%) [43]– in the exercise group.