When abnormalities are found using PSA screening, we need further screening measures: 1. Rectal examination: Rectal examination of the prostate is an effective way to diagnose prostate cancer. Prostate cancer mostly occurs in the posterior lobe of the prostate and the margins of both lobes, and the lesion is hard, so the nodules can be palpated in rectal finger position. The nodules are hard and uneven, and the central groove disappears. 2. Transrectal ultrasonography: The typical sign of prostate cancer is a hypoechoic nodule in the peripheral zone, and the size of the tumor can be initially determined by ultrasound (the volume of the prostate is determined by multiplying the lengths of the three diameters of the prostate and dividing by two, and the volume of the tumor is determined by multiplying the lengths of the three diameters of the tumor and dividing by two). The findings of a hypoechoic prostate lesion do not necessarily mean that it is prostate cancer, but may also be a normal prostate, a hyperplastic nodule from benign prostatic hyperplasia, PIN (prostatic intraepithelial neoplasia), acute or chronic prostatitis, or prostate infarction. And sometimes prostate tumors show up as isoechoic and cannot be detected on ultrasound. Prostate puncture biopsy: Prostate puncture biopsy is the most reliable test to diagnose prostate cancer. Therefore, transrectal ultrasound and other guided systemic puncture of the prostate is recommended. 3. Other imaging examinations for prostate cancer (1) Computed tomography (CT) examination: The purpose of CT examination for prostate cancer patients is mainly to assist clinicians in clinical staging of the tumor. (2) Magnetic resonance imaging (MRI/MRS) scan: MRI can show whether the prostate envelope is intact and whether it invades the surrounding tissues and organs of the prostate, MRI can also show the invasion of pelvic lymph nodes and bone metastases, so the main role of MRI is also reflected in the staging of the tumor. (3) Whole-body nuclide bone imaging (ECT): the most common site of distant metastasis of prostate cancer is bone. Once the diagnosis of prostate cancer is established, whole body nuclear bone imaging is recommended (especially in cases with PSA >20ng/ml and Gleason score >7) to help determine the accurate clinical stage of prostate cancer. To summarize the above, PSA, rectal examinations and transrectal ultrasound can suggest prostate cancer, but to confirm the diagnosis of prostate cancer, prostate puncture biopsy is necessary, while CT and MRI are mainly used to determine whether the prostate envelope is intact and whether there are enlarged pelvic lymph nodes, and whole-body bone scan is used to determine whether there are bone metastases, and these three examinations are mainly used to guide the staging after the diagnosis of prostate cancer is confirmed.