One of the best ways to start to reduce your risk of prostate cancer is see your doctor. Your doctor can screen you for prostate cancer with a DRE. During a DRE, a doctor inserts a gloved finger into the rectum and feels the surface of the prostate for any irregularities. Men of average risk for prostate cancer should be screened beginning at age 50.  African-American men and men with a family history of a first-degree relative being diagnosed with prostate cancer before age 65 should begin screening at age 40 or 45. The PSA test requires the doctor to take your blood and check the antigen levels in your system. Depending on your levels during your first test, the doctor may suggest different periods between testing. The higher your level of PSA, the more frequently you need to be tested. If you are found to have an extremely high PSA, your doctor will run more tests to see if your have prostate cancer.  According to the American Cancer Society, if your PSA is higher than 2.5 ng.mL, you should be retested every year. If your PSA is lower than 2.5 ng/mL, you may only need to be retested every two years.  If your PSA is between 4-10 ng/mL, there is a one in four chance that you will have prostate cancer. If it is higher than 10 ng/ml, your chance of having prostate cancer rises to over 50%.  Abnormalities uncovered by the DRE or the PSA test can be further investigated with a transrectal ultrasound (TRUS) and a biopsy if necessary. Your doctor can also prescribe medications that have the proven ability to reduce the risk of prostate cancer. In clinical trials, the drugs Avodart and Proscar reduced the risk of prostate cancer.  Currently, these drugs are only approved by the U. S. Food and Drug Administration (FDA) for the treatment of benign prostatic hyperplasia (BPH), which is nonmalignant enlargement of the prostate gland. As a result, these drugs have been used off-label for the prevention of prostate cancer, which means they are not approved for the prevention of prostate cancer by the FDA.

TL;DR in Vietnamese:
Thăm khám trực tràng bằng ngón tay (DRE). Xét nghiệm kháng nguyên đặc hiệu với tuyến tiền liệt (PSA). Hỏi bác sĩ về việc dùng thuốc.