Your care team looks at several pieces of information to understand how serious prostate cancer might be. One key test is a biopsy. During a biopsy, a doctor uses a hollow needle to take tissue from the prostate. That tissue is studied under a microscope to look for cancer cells. Prostate cancer often grows slowly. Slow-growing cancer may not cause serious problems. But sometimes prostate cancer grows quickly and spreads to other parts of the body. That kind of prostate cancer is considered serious. A screening test, like a PSA test, only tells you whether you might have cancer. It does not diagnose cancer or show how serious it is. If a screening test shows signs of cancer, more tests are needed. Those extra tests help show how serious the cancer may be. Your care team also looks at your age and general health when planning treatment. Ask your care team about your Gleason score and what it means for your own results.