Locally advanced and metastatic prostate cancer are diagnosed through physical exams and tests, including:

• A digital rectal exam, in which the doctor inserts a gloved finger into your rectum to feel your prostate gland. Some prostate tumors can be found this way.
• A PSA test to measure the levels of prostate-specific antigen (PSA) in your blood. A higher level of PSA may indicate an enlargement, infection, or cancer of the prostate. A rising PSA level after treatment for prostate cancer can mean your cancer has come back.
• A transrectal ultrasound, in which the doctor inserts a probe into your rectum to check your prostate. The probe uses sound waves (ultrasound) to create a picture of the prostate.
• A prostate biopsy, in which tissue is taken from your prostate and examined under a microscope. The other exams and tests can give clues that you may have prostate cancer, but only a prostate biopsy can tell for sure.

If you have had prostate cancer before, one or more tests will help your doctor see if your cancer has come back or spread. These may include:

• Blood tests. Different types of blood tests are used to see whether cancer has spread to your bones or liver.
• A bone scan. Radioactive material that shows up on X-rays is injected into your arm. An X-ray camera passes over your body, taking pictures as the radioactive material moves into your bones. Areas of bone damage show up in the pictures. Prostate cancer that has spread to the bones can cause this kind of damage.
• A CT scan. A CT scanner directs a series of X-ray pulses through your body. Each X-ray pulse lasts only a fraction of a second and represents a "slice" of the organ or area being studied.
• An MRI. An MRI uses a strong magnetic field to make pictures of the prostate. This can show tissue damage or disease, such as infection or a tumor.

Follow-up checkups

If you have been treated for prostate cancer in the past, you've probably been having regular checkups that include PSA tests to check for any signs that the cancer has come back or has spread to other parts of your body. Your doctor will watch for any increases in your PSA level and the speed with which any increases occur. A higher PSA does not necessarily mean your cancer has come back. But it may mean that you need further tests, such as a prostate biopsy, bone scan, CT scan, or MRI.