MIAMI BEACH--Cancer patients treated with strontium-89 (Metastron)
for palliation of their metastatic bone pain may also benefit
therapeutically, said Michael J. Katin, MD, a radiation oncologist
in Fort Myers, Florida, whose practice includes a significant
number of patients with painful bone metastases resulting primarily
from prostate cancer.
"Evidence is mounting to suggest that strontium-89 may retard
the progression of metastatic disease," Dr. Katin said at
a symposium on metastatic prostate cancer held in conjunction
with the American Society for Therapeutic Radiology and Oncology
(ASTRO) meeting.
Dr. Katin described the Trans-Canada Study, which tested the efficacy
of strontium-89 adjuvant to local field external beam radiotherapy
in 126 patients with multiple bone mets secondary to hormone-refractory
prostate cancer.
Patients treated with strontium-89 had a larger decrease in new
sites of pain, and significantly more of these patients reported
no newly painful sites, compared with the placebo arm (59% vs
34% for the two groups, respectively). Blood levels of serum tumor
markers were also significantly reduced in patients who received
strontium-89, compared with placebo-treated patients, during the
first 4 months after therapy.
Similar results were seen with the UK Metastron Investigators'
Group study, which compared strontium-89 treatment with external
beam therapy in 305 patients with painful prostatic metastatic
cancer. Significantly fewer patients who received strontium-89
developed new painful sites or needed additional therapy than
did those treated with radiation.
Since 1988, Dr. Katin has used strontium-89 in 229 patients. Overall,
76% had metastatic prostate cancer. Of these, pain decreased in
83% who were treated with a 50 µCi/kg injection; 13% had
total relief of their pain and were able to discontinue their
analgesics.
Dr. Katin emphasized that while he has not systematically examined
the question of whether strontium-89 provides therapeutic benefit,
he is nonetheless convinced that it has this property.