Multiparametric MRI in detection and staging of prostate cancer

Diagnosis of prostate cancer (PCa) PCa is suspected by elevated PSA and/or an abnormal digital rectal examination (DRE) and the diagnosis is made by transrectal ultrasound-guided biopsies (TRUS-bx) [2]. PSA PSA is a natural enzyme that is produced almost exclusively by the prostatic epithelial cells and is used as a serum marker for PCa. However, PSA is organ-specific, but not cancer-specific, as benign conditions such as benign prostatic hypertrophy (BPH), prostatitis and other urinary symptoms may cause elevated PSA levels. There is no absolute PSA cut-off level that indicates PCa and there is no PSA level below which a man is guaranteed not to have PCa, although the risk of PCa is associated with higher levels of PSA [3]. Traditionally, a threshold level = 4 ng/ml has been established as suspicious of PCa that trigger biopsies. However, at this cut-off level only about 1/3 men with elevated levels will in fact have cancer and "normal" levels may falsely exclude the presence of cancer, supporting the fact that PSA cannot be used to diagnose or exclude PCa [4-8]. The PSA level is also used in risk stratification of newly diagnosed PCa patients, included into predictive staging nomograms and for monitoring treatment response [2].