This is a study of men who have undergone a standard 10 or more core biopsy for detection of prostate cancer and determined to have prostate cancer by having a Gleason score ≤ 7 (low to moderate risk 2-7). Of these men, one arm of a two arm randomized group will be administered a treatment regime of Dutasteride versus the control group who receive standard of care, prior to mapping biopsy. This proposal aims at studying the apparent effect of the use of Dutasteride (3 months) on initial tumor volume (at diagnosis) in men with low volume cancer before undergoing 3D mapping biopsy.