How do doctors know if prostate hormone therapy is working?

Doctors mainly check the PSA level in the blood to see if hormone therapy for prostate cancer is working.

Doctors cannot predict how long hormone therapy will keep working for any individual man. So men who take hormone therapy for more than a few months are tested regularly to measure the level of PSA (prostate-specific antigen) in their blood.

An increase in the PSA level may mean that the cancer has started growing again or has become resistant to the hormone therapy being used. Most prostate cancers eventually become castration resistant, meaning they keep growing even when androgen levels are very low.

If your PSA rises, it does not mean you are out of options — some newer hormone therapies and other treatments can be used for castration-resistant prostate cancer. Your care team will use your PSA results, along with other tests, to guide your treatment.