PSA doubling time appears to be a reliable tool to distinguish which patients have prolonged innocuous PSA levels after therapy from those who are at great risk for disease recurrence and death from prostate cancer, according to researchers from the Mayo Clinic in Rochester, MN.

In a study of more than 1,000 patients with a calculable PSA doubling time, patients with a PSA doubling time of less than 3 months after therapy are at imminent risk of death from prostate cancer. Patients with a doubling time of 3 to 12 months are at a significant risk for the development of systematic disease and cancer-specific death, Michael Blute, MD, and colleagues reported in Mayo Clinic Proceedings (2007; 82:422-7).

According to Dr. Blute, the new findings should prompt physicians whose patients have doubling times of less than 1 year to treat them with systematic therapies. Patients with PSA doubling times of 1 to 10 years are more likely to have a local rather than systematic recurrence, and patients with a PSA doubling time of more than 10 years are at a low risk of recurrence.