I have a psa done once each year. along with various other blood tests, this is purely a routine check. however, as a matter of interest, is it true that the psa level never falls if a person has prostate cancer?

See below. : IF an elevated PSA is due to prostate cancer, then in the absence of treatment, one would not expect a significant, reproducible decline keeping in mind that there can be PSA variations within the body of 10-20%; not uncommon to have variations both within a specific lab and/or between different labs; and that one can have prostate cancer with PSA variations occurring for unrelated reasons.

Never say never: If there is an infarct in the gland and cancer, the PSA level may rise temporarily and then drop to the baseline level, which may be a high level in itself. Wish you good health!

Not true: PSA does fall if treatment ( for prostate cancer) is working, it might never be in normal range, but I have seen cases where it went from 3 digits( hundreds) to 1 digit (6-7) if the treatment works. PSA is otherwise no longer recommended to be checked yearly routinely for patients that are otherwise low risk for prostate cancer.