Recent Studies Raise Questions About
Effectiveness Of Radioactive Seed Implantation
by William J. Catalona, M.D.
After a decade of being abandoned,
the implantation of radioactive seeds for prostate cancer has become
popular again and is being marketed aggressively in many places.
of radioactive seeds was first popularized in the 1970s, but the
long-term results were unsatisfactory, at least in part because the
seeds could not be accurately placed by hand in the prostate gland.
Consequently, "seeds" were largely abandoned until the
late 1980s, when ultrasound guidance for seed placement was
two recent reports in medical journals have raised other questions
about the effectiveness of seeds as compared with radical
prostatectomy or external beam radiotherapy.
report is from the Pacific Northwest Cancer Foundation in Seattle,
Washington, where ultrasound-guided seed therapy was popularized.
In the publication, Cancer, Dr.
Haakon Ragde and his associates presented 10-year follow-up results
in two groups of patients:
low-risk group with low PSA, low Gleason grade, and low tumor stage
who were treated with seeds alone and a high-risk group with higher
PSA, higher Gleason grade and higher tumor stage who were treated
with seeds plus supplemental external beam radiotherapy.
results showed that in the low-risk group, the percentage of men who
remained free from tumor recurrence (measured by their PSA
remaining at less than .5) decreased by 19 percent.
7 years of follow-up, 79 percent of the men remained free from tumor
recurrence. At 10 years of follow-up, 60 percent of the men
were tumor free. The tumor recurrence rate is the same as that
achieved with the old hand-held techniques of seed implantation in
the tumor recurrence rate was higher in the low-risk patients who
received seeds alone than in the high-risk patients who received
both seeds and external beam radiotherapy. This finding
suggests that, even with ultrasound guidance, seed implantation
alone was not very effective.
another report in the Journal of the American Medical Association
from the Joint Center for Radiation Therapy at Harvard Medical
School and the University of Pennsylvania, Dr. Anthony V. D'Amico
compared the results of treatment with seeds, external beam
radiotherapy, and radical prostatectomy at 5 years of follow-up.
patients with low-grade tumors (Gleason 2-4), there was no
appreciable difference between the groups in tumor recurrence rate
after 5 years. However, for men with moderately (Gleason 5-7)
or poorly-differentiated (Gleason 8-10) tumors, patients treated
with seeds had a higher tumor recurrence rate than those treated
with either radical prostatectomy or external beam radiotherapy.
together, these studies suggest that, in the long term, seeds alone
may not be adequate treatment for many patients with early-stage