Overall, of the 223 patients, 106 (48%) were found to have a tertiary pattern, which on average, was 7% of the total tumour volume. Patients with a tertiary pattern had a 5-year risk of PSA progression of 37.3% versus 12.6% in case no tertiary Gleason pattern was present (log rank p=0.0002). There was no prognostic difference between patients with a higher-grade tertiary pattern as compared to those with a lower grade tertiary pattern.