Long-term survival in prostate cancer patients can be predicted by prostate-specific antigen (PSA) values at 2 years posttreatment, say researchers from Memorial Sloan-Kettering Cancer Center.
According to background information provided by the authors, PSA levels in a prostate cancer patient are monitored after a patient’s treatments, and after a successful course of external beam radiation therapy (EBRT) the levels should decline gradually over the following 18-24 months.
To determine the significance of a patient’s reaching a certain PSA level at a specific point in time post-EBRT, Michael Zelefsky, MD, lead author of the study and a radiation oncologist at Memorial Sloan-Kettering Cancer Center, led a team of researcher in a study that focused on a fixed point after treatment to predict patient outcomes.
Researchers found that prostate cancer patients who had a prostate-specific antigen (PSA) value of £ 1.5 at 2 years after EBRT were less likely to experience cancer recurrence and cancer-related death. Patients with this PSA value at 2 years posttreatment had a 2.4% incidence of distant metastases at 5 years after treatment and a 7.9% incidence at 10 years after treatment. Additionally, patients with a PSA value > 1.5 experience a significantly higher rate of metastases at 5 and 10 years after treatment (10% and 17.5%, respectively).
“In the past, patients with a relapsing cancer after receiving radiation were not identified until several years after treatment and at that point it may be too late to effectively salvage their recurrence,” Dr Zelefsky. “If we can catch these future instances of cancer recurrence earlier in prostate cancer patients, then we have a much higher chance of reducing the mortality associated with the cancer.”
The findings were published in the International Journal of Radiation Oncology, Biology, and Physics (2009;75:1350-1356).