Overduin CG, et al. - This study was conducted to evaluate iceball margins after magnetic resonance (MR)-guided focal salvage prostate cryoablation and to ascertain the correlation with local outcome. Iceball margins seem to correlate with local outcome following MR-guided focal salvage prostate cryoablation. This initial information recommends that freezing must be applied at minimum 5 mm beyond the border of an MR-visible recurrent prostate tumour for successful ablation, with a wider margin appearing desirable.