NEW YORK, Feb 01 (Reuters Health) -- A radioactive substance used to
relieve bone pain in men with advanced prostate cancer may also increase the
risk of leukemia, researchers report.
At least two men have developed acute myelogenous leukemia -- a dramatic
increase in the number of white blood cells -- after they received the
pain-relieving compound known as strontium-89, according to a report in the
February 1st issue of Cancer.
Because strontium-89 is being used more frequently and earlier in the
course of the disease, a diagnosis of leukemia in prostate cancer patients could
become more common, according to Dr. Mark A. Weiss of the Memorial
Sloan-Kettering Cancer Center, and Dr. Steven E. Kossman of Cornell University
Medical College in New York.
Historically, strontium-89 has been used in patients who did not live long
enough to develop leukemia, they explain. The radioactive isotope relieves pain
because it is processed in the body in a similar manner as calcium and is
deposited in areas of bone invaded by cancer cells.
According to the report, a 74-year-old man who had his prostate removed in
1983 due to cancer, relapsed and the cancer spread to his bone in 1995. In 1996,
he developed skeletal pain for which he received strontium-89.
In 1998, the patient began developing symptoms of acute myelogenous
leukemia and after treatment failed, eventually died in the hospital.
In the second case, a 70-year-old male with prostate cancer that had also
spread to the bone received injections of strontium-89 in 1996 and 1997. The
patient also received two anti-cancer drugs but ultimately died in December of
1998.
While "there is little doubt" that strontium-89 may cause leukemia, it is
not clear from the study if it was the cause of leukemia in the prostate cancer
patients, according to an editorial by Dr. Wallace Akerley of Boston University
Medical Center in Massachusetts.
Strontium-89-related leukemia cases have been seen in atomic bomb
survivors, he notes. However, the men in the study were exposed to the isotope
for a relatively short period of time, and the leukemia may have been caused by
some other factor related to treatment, such as chemotherapy, according to
Akerley. The apparent link may also be a coincidence, he said.
Overall, "it would appear that the risk of developing acute myelogenous
leukemia after exposure to strontium-89 is low," he writes. The two cases do
"support the need for even closer monitoring," Akerley concludes.
