The prostate is a small gland which surrounds the urethra. It is located underneath the bladder and in front of the rectum.
One of the functions of the prostate is to produce and transport prostatic fluid. During an orgasm this fluid mixes with sperm and is ejaculated out of the penis.
PSA (Prostate Specific Antigen) is a protein, found in the blood. It is produced exclusively by the prostate, but not exclusively by prostate cancer.
An elevated concentration of PSA can be related to the presence of prostate cancer, but may also point toward other benign conditions of the prostate, such as benign enlargement (BPH) or infection/inflammation.
PSA may be artificially low after surgery for benign enlargement of the prostate (BPH) or with the use of drugs against this condition.
An elevated PSA test may detect a slow growing tumour which would otherwise never have given trouble.
Above the age of 50 however approximately 2 in 10 men (20%) have an elevated PSA value. The elevated value can point toward prostate cancer but may also be related to benign prostatic enlargement, a urinary tract infection or an infection of the prostate.
For this reason additional studies are always necessary if a PSA value is found to be elevated. However, the chance of having prostate cancer increases with higher PSA values.
80% of men above 50 have a normal (not elevated) PSA value. The PSA test can miss prostate cancer. Men with a completely normal PSA test can have a (usually small) prostate cancer. This applies to at least 1 in 100 men (1%).