Here is a thought provoking article from Australia’s Rheumatology Update:
Evidence grows of CT-cancer link, but experts still divided
The jury is still out on the link
between medical imaging and
cancer, despite research claiming
to offer some of the strongest
evidence to date, an expert says.
While the issue hit the headlines
in Australia with calls to
stop unnecessary imaging,
debate has been rumbling among
radiologists as to the exact
strength of the association.
A Canadian study published this
week reported a dose-dependent
relationship between radiation and
cancer, after following over 80,000
patients who had undergone
cardiac imaging after acute MI.
Every 10mSv of low-dose
ionising radiation increased the
risk of cancer by 3% over five
years, the researchers said.
Cancers of the abdomen, pelvis
and thorax were the most common,
accounting for about two-thirds of
the 12,000 cancers that developed
over the study period. Bone, skin
and soft tissue cancers accounted
for 22%, head and neck cancers
9%, and blood cancers 8%.
However, Associate Professor
Stacy Goergen, director of
research in the Department of
Diagnostic Imaging at Melbourne’s
Southern Health, said methodological
problems meant the
study was “not at all definitive”.
There was no control group
and no proper adjustment for
confounding factors, she said,
noting the sickest, most cancerprone
patients would be most
likely to undergo imaging.
Although evidence overall pointed
to an increased risk of cancer
after medical imaging, particularly
breast cancer, she urged people to
wait for more robust studies, such
as one ongoing at the University
of Melbourne. The researchers are
comparing long-term outcomes
from children exposed to CT in
the 1980s against controls.
The debate between radiologists
continued last week in the
Medical Journal of Australia.
Responding to earlier claims
from fellow Melbourne radiologist
Dr Carl Blecher that alarm about
CT scans was unjustified as it was
based largely on theoretical extrapolations
from the 1945 atomic
bombs, Professor Goergen and
colleagues reasserted the need
to keep exposure to a minimum.
Ongoing CT optimisation
programs in Australia had already
shown the potential for many
centres to cut down their radiation
exposure, the letter said, adding
the cumulative effect of CT scans
was “not necessarily trivial”.
I have written many times about the potential danger of radiation from CT scans and other diagnostic tests. Here are links to a few of them:
New digital imaging in x-ray technology has helped reduce radiation exposure there. CT scans continue to pose a risk. What I can’t answer is if the risk justifies getting the diagnostic image your physician needs to make a diagnosis.
No one argues one or two scans are a significant danger. But one every two or three months?
Personally, I am willing to take the risk. I do that each month when I agree to take an oral chemotherapy agent, Revlimid, even as reports are surfacing that it may cause secondary cancers.
Did our parents warn us we would be forced to make such difficult decisions once we became adults? Did any of us ever think it would be so hard when we were teenagers? Sigh!
Feel good and keep smiling! Pat