In an article by Vargas et al published in J Urol (2012), the authors showed that MRI could predict aggressive prostate cancer in patients initially thought to have low risk prostate cancer. Such upgrading is a barrier to the acceptance of active surveillance for men with prostate cancer. A total of 388 consecutive men (mean age 60.6 years, range 33 to 89) with clinically low risk prostate cancer (initial biopsy Gleason score 6 or less, prostate specific antigen less than 10 ng/ml, clinical stage T2a or less) underwent MRI before confirmatory biopsy. Three radiologists independently and retrospectively scored tumour visible on MRI using a 5-point scale (1—definitely no tumour to 5—definitely tumour). Associations between magnetic resonance imaging scores and confirmatory biopsy findings were evaluated.
On confirmatory biopsy, Gleason score was upgraded in 79 of 388 (20%) patients. Magnetic resonance imaging scores of 2 or less had a high negative predictive value (0.96–1.0) and specificity (0.95–1.0) for upgrading on confirmatory biopsy. A magnetic resonance imaging score of 5 was highly sensitive for upgrading on confirmatory biopsy (0.87–0.98).
The authors concluded that MRI was useful in the selection of patients for management with active surveillance.