PSA is a blood test that can detect prostate cancer in the early, curable stages. These early stages of prostate cancer often produce no symptoms. PSA measures the levels of prostate-specific antigen (PSA), a molecule shed into blood by prostate cancer cells.

Prostate cancer is the most common male cancer, accounting for nearly 30% of new cases. It is the second leading cause of male cancer deaths, after lung cancer. Prostate cancer arises in the cells of the prostate gland, which is a walnut-shaped organ that lies between the bladder and rectum. The prostate’s normal function is to produce fluid for the sperm. Prostate cells have the potential to transform into cancer cells, which can invade other parts of the body.

African American men, and men with a relative who’s had prostate cancer are at increased risk. Taking the drug finasteride may prevent prostate cancer, but could bring on a more aggressive form of the disease.

Prostate cancer often comes without symptoms in the early stages, although difficulty urinating or blood with ejaculation could be early warning signs. More advanced prostate cancer, which has spread throughout the body, can cause bone pain, weigh loss, and generalized weakness.

Early detection is important, because treatment in the early stages can result in cure. Some early prostate cancers are found when a prostate nodule is detected by rectal exam. PSA testing can also detect early prostate cancer. If PSA is high or a nodule is found, a prostate biopsy is done by inserting a small ultrasound into the rectum (to visualize the nodule), then using a needle to remove some tissue. If cancer is present, further treatment may be recommended. Not everyone with high PSA turns out to have prostate cancer; other conditions, such as inflammation of the prostate, can elevate the PSA.