In 50 men with prostate cancer managed by active surveillance, changes in diffusion and perfusion within normal prostate and tumor were compared between those whose tumors did (“Growers”) or did not grow. 14% had >50% increase in tumor volume on MRI at 1-year. In these men, ADC of normal PZ was lower and more homogenous and remained unchanged over time; vascular metrics also remained stable. In TZ, no changes occurred in ADC or vascular metrics. In tumor, Kep increased with time in growers and ADC histogram metrics showed a left-shift indicating changes in tumor vascular and cellular microstructure with progression.