To determine the role of staging pelvic magnetic resonance imaging (MRI) in men with intermediate risk prostate cancer.

We identified all patients diagnosed with intermediate risk (NICE definition: PSA 10–20 ng/ml, or Gleason score 7, or clinical stage T2b/T2c) prostate cancer between 1st January 2007 and 31st December 2008. Through retrospective case note review, we determined the number of patients who had undergone a pelvic MRI and whether such an investigation had altered the patient’s management by increasing tumour stage.

A total of 222 men (mean age 66 years; range: 48–88) were diagnosed with intermediate risk prostate cancer during our study period. The mean PSA was 11.8 ng/ml (range: 3–20 ng/ml). Of these, 112 (50.5%) underwent an MRI. Overall, in 25/112 (22.3%) patients, pelvic MRI findings impacted significantly upon patient treatment by demonstrating either extra-prostatic extension of cancer, lymph node involvement or bone metastases.

Our retrospective study has demonstrated that a pelvic MRI in men diagnosed with intermediate risk prostate cancer may influence treatment decision in approximately a quarter of patients. Routine pelvic MRI is indicated in men with intermediate risk prostate cancer where radical treatment is contemplated.