Physicians can usually determine the clinical outcome of prostate cancer patients treated with hormone therapy and radiation therapy by how rapidly their prostate specific antigen (PSA) level rises following treatment, according to a report published in the Oct. 1st issue of the International Journal of Radiation Oncology*Biology*Physics, the official journal of ASTRO.
Doctors at M.D. Anderson Cancer Center in Houston studied 621 men with prostate cancer treated with hormone and radiation therapy between 1989 and 2003 to determine whether clinical failure after their treatment correlated with the speed at which their PSA level rose following treatment. Clinical failure was defined as cancer recurring in the prostate or spreading to other parts of the body.
Researchers found that measuring how quickly the PSA level doubled was a good indicator of subsequent poor clinical outcomes, including cancer developing in other parts of the body or death related to prostate cancer. Patients whose PSA level doubled within eight months after treatment failure were more likely to have the cancer return or spread to other parts of the body than patients whose PSA did not double in eight months or less. The estimated five-year rate of clinical failure for patients with a PSA doubling time of more than eight months was only 9.4 percent while 60.4 percent of patients whose PSA doubling time was less than or equal to eight months could expect some type of clinical failure.