[Prostate specific antigen and diagnosis of prostate cancer]

Prostate cancer had a development predominantly at peripheral gland and stay for a long time asymptomatic without clinical symptoms. When the cancer is symptomatic, it is often translate an advanced stage. The symptoms of prostate cancer are not specifics: urinary troubles, compression of iliac vessels or bone metastases pain. The digital rectal examination highlight an induration nodule, irregular and painless. The probability to have a cancer increase with the rate of the prostate specific antigen (PSA). Some others situations can increase the rate of PSA: benign prostatic hyperplasia, prostatitis, bladder catheterisation, urinary retention, endoscopic examination. The ratio of free-PSA/total-PSA (fPSA/tPSA) permits a best discrimination between benign prostatic hyperplasia and prostate cancer The more fPSA/tPSA ratio is low, the more the risk of prostate cancer is high. Prostate cancer is suspected with the digital rectal examination and the rate of PSA but the diagnosis is made by histological examination (the tissue samples are took by transrectal ultrasound-guided biopsies). The staging of disease must be realised according to the risk of metastasis appreciated by clinical stage, rate of PSA and Gleason score.