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 results of a
"look-back" study of 635 men by Johns Hopkins Medical
Institutions researchers reported June 18 in
the Journal of the American Medical Association.
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, 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," Trock said.
"I found the results of this study remarkable," said
Patrick C. Walsh, 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 percent to 40 percent of men with
high-risk tumors experience no recurrence
of their cancers after surgery and can be spared the side
effects of 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.
Theodore L. DeWeese, professor and chairman of the
Department of Radiation Oncology and
Molecular Radiation Sciences, said, "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. 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.
In addition to Trock, Walsh and DeWeese, the research
team included Misop Han, Elizabeth B.
Humphreys and Alan W. Partin, all of the Brady Urological
Institute at Johns Hopkins; and Stephen J.
Freedland, of the Durham Veterans Affairs Medical Center
and Duke University School of Medicine.
Funding for this study was supported in part by the
National Cancer Institute, gifts by Dr. and
Mrs. Peter S. Bing, the Department of Defense Prostate
Cancer Research Program and the American
Urological Association Foundation's Astellas Rising Star in
Urology.