PSA or Prostate-Specific-Antigen is a type of protein produced in the prostate. According to the American Cancer Society PSA is found in semen, but small amounts can also be found in the male bloodstream. Generally the higher your PSA level, the greater your risk of prostate cancer.
According to the American Cancer Society healthy males have levels under 4 ng/ml (nanograms per millilitre) of blood. A level of seven would put you between 4 and 10, giving you a 1 in 4 chance of having prostate cancer. Any level above 10, gives you a 50 per cent chance.
Conditions such as BPG (benign prostatic hyperplasia), a non-cancerous swelling of the prostate gland, an infection, inflammation or natural ageing can also make PSA levels rise.
Some men with a PSA level below four can also have prostate cancer. For instance, overweight men can maintain a low PSA level, even if they have cancer.
Early prostate cancer often shows no signs. Advanced forms can be noted by impotence, blood in the urine, loss of bladder or bowel control. Bone pain can also be prevalent.
PSA tests are controversial mainly because there are instances where either false-positives or false-negatives can adversely affect the patient. Of course a false negative could be life-threatening. It's always important to discuss when and if you need a prostate exam with your doctor.