PSA, including total PSA and free PSA, needs to be reviewed regularly after prostate cancer surgery. if blood PSA > 0.2ng/mL, biochemical recurrence is considered, then there are micro metastases or tumor residue, especially for patients with positive cut margins or micro metastases in pelvis, if PSA value is elevated, it needs to be highly alert to recurrence signs. In addition, the shorter the doubling time of PSA in prostate cancer, the faster the tumor progression. If the PSA value is very high, imaging tests, including MRI and PSMA tests, and whole-body scans are needed to identify recurrent lesions and treat them with surgery or radiation therapy.