Hypofractionation in prostate cancer was studied in the Phase III NCIC Clinical Trials Group PR-5 study. The long term outcomes were reported at ASTRO in November of 2003. The results of the PR-5 study, together with a similar Australian randomized trial reported in 2003, strongly support the biological model of a high fractionation sensitivity of prostate cancer, which can be exploited using hypofractionated radiotherapy.