I. Rectal examination Rectal examination is the main method to diagnose early prostate cancer. Since the prostate is close to the front of the rectum, it is easy to understand the condition of the prostate through rectal examination. Under normal conditions, the size of the prostate gland is about 4cm x 3cm, with a soft texture, smooth surface, no nodularity and symmetry between the two lobes. When the prostate gland is enlarged, the rectal examination will reveal that the size of the prostate gland has increased, but the texture is not very hard. In the case of prostate cancer, the surface of the prostate will not be smooth and sometimes you can feel the nodules of the tumor, and if the tumor is large, the texture of the entire prostate will become hard, like a stone. 2. Transrectal ultrasound examination The previous part has talked about the role of transrectal ultrasound examination in the diagnosis of benign prostatic hyperplasia, in fact, it also has a very important significance in the diagnosis of prostate cancer. Early stage prostate cancer patients can find abnormal nodules in the prostate gland during the examination. This is very helpful for the clinical staging and prognosis of prostate cancer. Prostate-specific antigen Prostate-specific antigen is the most sensitive tumor marker for prostate cancer. Although PSA can also be detected in the blood of normal people, when PSA rises to a certain value, it is highly indicative of the presence of cancer cells in the prostate. A study found that of the 473 patients with prostate cancer suspected and eventually diagnosed by PSA testing, 40% had no abnormalities on DRE testing. Currently, the widespread clinical use of PSA testing has led to the diagnosis of prostate cancer 5 to 8 years earlier in many patients, thus providing a life-saving opportunity early in the course of the disease. These three tests are now considered by urologists as the three main “magic weapons” for early diagnosis of prostate cancer. With these three powerful weapons, doctors are able to detect cancer cells hidden in the prostate as early as possible. The American Cancer Society now recommends these three tests as health screenings for older men. Rectal exams and serum PSA are the “first-line” tests and transrectal ultrasound is the “second-line” test. In other words, for older men over 50 years of age, DRE and PSA should be performed annually, and if abnormalities are found, TRUS should be proactively performed and further managed on a case-by-case basis.