Doctors perform the prostate-specific antigen test to screen men for prostate cancer, determine when to begin prostate cancer treatment and judge the effectiveness of the treatment, explains Mayo Clinic. Doctors also use the test to determine whether prostate cancer has returned or spread, according to WebMD.
Doctors perform the PSA test to screen for prostate cancer before recommending a biopsy, explains Mayo Clinic. If the results of a digital rectal exam are abnormal, the PSA test may provide additional information on the possible presence of prostate cancer, reports WebMD. During active surveillance, doctors use this test to determine whether the prostate cancer is spreading or growing. An increase in PSA levels after removal of the prostate gland indicates recurrence or spread of the prostate cancer.