The clinical significance of prostate specific antigen (PSA)

1. Screening
        ① PSA can be used as an indicator of individualized screening for prostate cancer. The screening is mainly for middle-aged and elderly men, and the screening age can start from 55 years old; for high-risk groups of prostate cancer, such as men with a family history of prostate cancer, it can start from 45 years old.
        ② Screening for prostate cancer should include PSA testing and digital rectal examination.

2. Auxiliary diagnosis
        ① When the serum PSA concentration is ≥4.0 μg/L, a digital rectal examination (DRE) inspection should be performed.
        ② In the gray area where the serum PSA concentration is between 4.0 μg / L and 10.0 μ g / L, if DRE is positive, a prostate biopsy should be performed to confirm the diagnosis. If DRE is negative, the percentage of free PSA (%fPSA) should be tested. If %fPSA<10%, a prostate biopsy should be considered to confirm the diagnosis.
        ③ If the serum PSA concentration is more than 10.0 μg/L, prostate biopsy should be done to confirm the diagnosis.
        ④ The rate of serum PSA is accelerated, increasing at a rate of ≥0.75 μg/(L ·year). After excluding the influencing factors of PSA testing, prostate biopsy should be done. This test is more suitable for young patients with low PSA values.
        ⑤ The PSA density test can help distinguish between prostate hyperplasia and the elevated PSA caused by prostate cancer. If the PSA density is ≥0.15, after excluding the influencing factors of PSA test, it can guide the doctor to decide whether to perform prostate biopsy.
        ⑥ The composite PSA (cPSA) test is not yet recommended for clinical use, but it can be used for medical research.

3. Efficacy and recurrence monitoring
        ① Serum PSA determination helps to monitor the response of prostate cancer patients to treatment. After 4 to 6 weeks of prostate cancer eradication surgery, the serum PSA concentration drops below the detection limit, indicating that the operation is effective; if the serum PSA concentration drops only partly, it indicates that the operation is incomplete, there are residual lesions or there are prostate cancer metastases.
        ② The determination of serum PSA has reference value for monitoring the recurrence of prostate cancer.
        ③ Serum PSA should be tested every 3 months during the first 2 years after the eradication of prostate cancer, every 6 months after 2 years, and once a year after 5 years. During the monitoring, if the serum PSA concentration rises twice in a row, it indicates a biochemical recurrence of prostate cancer.