To investigate whether multiparametric MRI (mp-MRI) in patients with low-risk prostate cancer can improve the selection of patients suitable for Active Surveillance and have a relevance in the ongoing monitoring.

Men with localized prostate cancer (PCa) with small tumor burden may be followed on active surveillance (AS) rather than active treatment. AS is an attempt to avoid over-treatment of PCa, which is estimated to be insignificant at the time of diagnosis, and therefore unlikely to affect patient morbidity and mortality. AS include close monitoring with PSA measurement (blood test), digital rectal exploration (DRE) and trans-rectal ultrasound-guided prostate biopsy (TRUS-bx) at regular intervals, so that active treatment can be initiated if the cancer becomes more aggressive. It is crucial that patients undergoing AS are staged correctly, to avoid underestimating more aggressive disease and patients mistakenly are enrolled into AS instead of active treatment.

Previously, a PhD study conducted at Herlev Hospital revealed that multiparametric MRI (mp-MRI) of the prostate can improve the detection and staging of PCa and may add additional information about tumor aggressiveness compared to the traditional methods DRE and TRUS-bx. Mp-MRI at the inclusion of AS may detect missed significant tumors and potential areas of higher aggressiveness than detected by the traditional biopsies. Additional targeted biopsies from these suspicious areas can then be performed with a re-evaluation of the treatment plan, if more advanced disease is identified. Conversely, mp-MRI has a high negative predicted value for significant disease and can be used to rule out significant PCa, reassuring patients and physicians to go on with AS. Mp-MRI has been used at the Urology Department, Herlev Hospital, since 2013 in the diagnosis of PCa and in the evaluation of patients undergoing AS. The main objective of this study is to retrospectively investigate, whether mp-MRI can improve the selection of patients suitable for Active Surveillance and have a relevance in the ongoing monitoring.

Inclusion Criteria:

• Patients with low risk localized prostate cancer enrolled in active surveillance

Exclusion Criteria:

• Metastatic prostate cancer
• No mp-MRI data present
• Prostate cancer treatment
• Known allergic reaction to Gadolinium-based MRI contrast agent
• Prostate biopsy during the last 21 days
• Impaired renal function with GFR < 30 ml / min
• pacemaker
• Magnetic metal residues in the body
• Claustrophobia
• Psychiatric disorders
• Age under 18 years

Men with newly diagnosed low-risk prostate cancer enrolled in active surveillance at Dept. of Urology, Herlev University Hospital, from Januar 2013 to June 2015, who have had an mp-MRI of the prostate in their diagnostic follow-up.