MONDAY, Feb. 7 (HealthDay News) -- Heart attack
patients who are exposed to low-dose radiation from cardiac imaging
and other procedures may have an increased risk of cancer, a new
study finds.
Canadian researchers analyzed data from 82,861 patients
who survived a heart attack between April 1996 and March 2006 and
had no history of cancer. Within one year of their heart attack, 77
percent of the patients underwent at least one cardiac procedure
with low-dose ionizing radiation, such as CT angiography and
nuclear scans.
Patients treated by a cardiologist had higher levels of
exposure to radiation than those treated by a general practitioner,
the study authors noted.
During follow-up, there were 12,020 cancers detected
among the patients, with two-thirds of the cancers affecting the
abdomen/pelvis and chest areas.
"We found a relation between the cumulative exposure to
low-dose ionizing radiation from cardiac imaging and therapeutic
procedures after acute myocardial infarction [heart attack], and
the risk of incident cancer," wrote Dr. Louise Pilote, an
epidemiology researcher at the Research Institute of the McGill
University Health Center (MUHC) in Montreal, and director of the
internal medicine division at MUHC, and colleagues.
"Although most patients were exposed to low or moderate
levels of radiation, a substantial group were exposed to high
levels and in general tended to be younger male patients with fewer
comorbidities [co-existing health problems]," they added.
"These results call into question whether our current
enthusiasm for imaging and therapeutic procedures after acute
myocardial infarction should be tempered," the researchers
concluded. "We should at least consider putting into place a system
of prospectively documenting the imaging tests and procedures that
each patient undergoes and estimating his or her cumulative
exposure to low-dose ionizing radiation."
The study appears in the current issue of
the Canadian Medical Association
Journal.