The PSA test is used as a guide to estimate the risk that cancer is present or is likely to develop in the future. It is not always accurate when used in this way and many men with high PSA levels do not have cancer.
PSA is of particular use after prostate cancer diagnosis, when it can be an indicator of how far the cancer has grown (stage) and for monitoring the success of treatment.
PSA is also used together with other clinical measures such as tumour grade (Gleason score) to assess the risk posed by a particular cancer, and so the type of treatments that might be needed and their likely outcome.
