Prostate cancer is one of the most common malignancies of the male genitourinary system. Epidemiological studies have shown that the occurrence of prostate cancer is mainly related to factors such as age, race, family genetic background, geographic location and dietary structure. The incidence of prostate cancer varies widely worldwide, with the incidence rate in Asians being much lower than that in Europe and the United States. In the United States, the incidence of prostate cancer ranks first among all malignant tumors in men, and the mortality rate is second only to lung cancer. Unlike other common malignant tumors of the urinary system, prostate cancer does not have typical clinical symptoms because it occurs mostly in the peripheral zone of the prostate gland, and early prostate cancer is mostly confined to the prostate gland and does not invade the surrounding tissues of the prostate gland, so there are often no obvious clinical manifestations. However, with the development of the tumor, it will show many different clinical symptoms. 1.Lower urinary tract symptoms: including irritation symptoms and obstruction symptoms. First of all, it should be clear that lower urinary tract symptoms are not unique to prostate cancer, but more often seen in many benign urological lesions. In patients with prostate cancer, lower urinary tract symptoms can be caused when the tumor infiltrates into the anterior middle of the prostate and invades the urethra, bladder neck and triangle. The symptoms include frequent urination, urgent urination, hesitant urination, interruption of urination, dribbling after urination and straining to urinate, etc. Local infiltrative symptoms: The growth and development of prostate cancer tend to develop along the weakest pathway. Most prostate cancers originate in the peripheral zone of the prostate, that is, in the posterior part of the prostate, so the cysto-rectal space is often the first area invaded by local infiltrative prostate cancer. If the tumor invades the prostate envelope and its adjacent perineural lymphatics, it may cause perineal pain and sciatica; if the tumor invades the vas deferens, it may cause low back pain and testicular pain; if the tumor invades the upper part of the cysto-rectal space, it may compress the ureter and cause unilateral or bilateral hydronephrosis, which may lead to renal failure. If the tumor invades the neurovascular bundle at the back of the prostate gland, it will lead to erectile dysfunction. Metastatic symptoms: The most common metastatic site of prostate cancer is bone, and sometimes it may also metastasize to other organs, such as lung, liver and adrenal gland. Bone metastasis of prostate cancer may cause bone pain and even pathological fracture; tumor metastasis to pelvic lymph nodes may cause lower limb edema; tumor metastasis to lung may cause coughing and coughing blood, etc. 4. Systemic symptoms: late stage prostate cancer may manifest as wasting and weakness, low fever, progressive anemia, cachexia or renal failure. It can be seen that the early symptoms of prostate cancer patients are atypical and cannot be detected through early clinical manifestations, while prostate cancer is often at an advanced stage when certain clinical symptoms appear. Since the key to improving the treatment effect of prostate cancer is early diagnosis and early treatment, prostate cancer screening is especially important for the treatment effect of the disease. Screening for prostate cancer refers to the application of simple and effective screening methods to detect the tumor early before the patient develops the related symptoms. The most common screening methods include rectal examination, prostate-specific antigen test and transrectal ultrasound, among which rectal examination and PSA test are the most common and basic screening methods.