Radiation therapy may increase survival rates in patients with recurrent prostate cancer, researchers at the Johns Hopkins Medical Institutions have found.
Men whose tumors recur after prostate cancer surgery are three times more likely to survive their disease long term if they undergo radiotherapy within two years of the recurrence. Surprisingly, survival benefits were best in men whose new tumors were growing fastest, according to the "look-back" study of 635 men.
Previous studies of radiation therapy for recurrent prostate cancer found that it reduced disease progression, but this study demonstrates that it significantly prolongs survival, as well, according to Bruce J. Trock, Ph.D., associate professor of urology, epidemiology, oncology, and environmental health studies, and director of the Division of Epidemiology in the Brady Urological Institute at Johns Hopkins.
"What this new study tells us is that even men with aggressive disease that has recurred after surgery appear to benefit from radiation therapy. It also means that we may be able to give radiation selectively to those who are really likely to benefit from it," said Trock.
"I found the results of this study remarkable," said Patrick C. Walsh, M.D., University Distinguished Service Professor of Urology at the Brady Urological Institute.
Previously, we believed that these men -who have aggressive disease defined by a rapid doubling of PSA in six months or less -- had distant metastases and would not benefit from any form of local salvage therapy."
PSA, or prostate specific antigen, is the blood-based protein shed by the organ that signals the likely presence of cancer. Rapid rises in PSA levels after surgical removal of the prostate signal the recurrence of cancer and often convey a poor prognosis.
Approximately 30 to 40 percent of men with high-risk tumors experience no recurrence of their cancers after surgery and can be spared the side-effects, that is, urinary and bowel problems, that may come with radiation.
So, the Johns Hopkins researchers were looking to determine whether radiation could improve survival in men with recurrent prostate cancer and the optimal timing for the therapy.
In the new study, the researchers reviewed records of 635 men who developed recurrent cancer following radical prostatectomy at Johns Hopkins Medical Institutions between June 1982 and August 2004. Of these, 397 received no salvage radiation therapy, 160 received only salvage radiation, and 78 received both salvage radiation and hormonal therapy. Median follow-up was six years after recurrence.
Among men who had received radiotherapy for prostate cancer recurrence, the probability of surviving 10 years was 86 percent, compared to 62 percent among those who did not have radiation. For patients with rapidly growing tumors, defined by a PSA doubling time of less than six months, the benefits of salvage radiation therapy existed regardless of Gleason score, a numerical value that measures prostate cancer aggressiveness.
"This review suggests that even patients with aggressive cancer at the time of surgery not only benefit from salvage radiation therapy, but also actually live longer without a second prostate cancer recurrence," said Theodore L. DeWeese, M.D., professor and chairman of the Department of Radiation Oncology and Molecular Radiation Sciences.
"This is the most important news for this group of patients in a long time."
DeWeese suggests that radiation oncologists and urologists now consider salvage radiation therapy for a broader group of patients with recurrent prostate cancer following surgery.
The study is published June 18 in the Journal of the American Medical Association.