Men who experience a reoccurrence post surgery will usually be referred for salvage radiation therapy. The goal of the radiation is to simply eliminate the stray cancer cells that might have remained in the prostate bed. The only way we currently have to monitor the outcomes from this radiation is to monitor PSA. Researchers at Fox Chase claim there is a better way to monitor outcomes after this procedure.
A team led by Mark Buyyounouski, M.D., M.S., radiation oncologist at Fox Chase, will present some research results at the annual meeting of the American Society for Radiation Oncology. He found that the levels of a prostate-specific protein up to 18 months after salvage radiation therapy can predict eventual mortality and progression of the disease post radiation.
Dr. Buyyounouski said, “It’s important because if you can identify people who are more likely to die of prostate cancer early, you can talk with them about doing another treatment very quickly, with the hope that it will prolong their lives.”
Men who receive primary radiation therapy who reach a PSA level of 2 ng/mL within 18 months after primary radiation treatment are assumed to have a disease spread and do have a higher mortality rate. Buyyounouski asked whether the same criterion is important for men who receive radiation after surgery.
The researchers looked at 222 men who had salvage radiation therapy at Fox Chase between 1991 and 2007. They found that roughly half of the men who surpassed the 2.0 threshold PSA levels within 18 months after treatment experienced spread of the disease or died within five years. By contrast, men whose PSA levels did not reach the threshold within 18 months did not die within five years. Further the likelihood that the disease metastasized was only 17% during that time period. The more quickly the PSA rises, the greater the likelihood the disease will attack other organs and cause death.
“These results provide us with an opportunity to identify men who should be treated aggressively, before we see any other evidence of prostate cancer,” Buyyounouski says. On the other hand, men who approach a PSA level of 2 ng/mL 18 months after treatment or later may not require immediate hormonal therapy, he adds.
To confirm the findings, Buyyounouski and his team will next extend the investigation to multiple institutions and a larger set of patients.
Co-authors include Tianyu Li, Aruna Turaka, David Y.T. Chen and Eric M. Horwitz.
Joel T Nowak, M.A., M.S.W.