Risk of radiation-induced cancer from imaging overemphasized

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The lifetime radiation risk of developing cancer associated with medical imaging exams may be overestimated relative to the immediate health risks, according to an article published online in the journal Radiology.

Pari Pandharipande, an abdominal and genitourinary imaging specialist at Massachusetts General Hospital and Harvard Medical School, and colleagues used computed tomography radiation dose data and mathematics to analyze the outcomes of testicular cancer patients who underwent CT surveillance for 10 years following the removal of the testicle. They projected that, as an example of the evidence yielded from the study, 33-year-old men with stage 1 seminoma undergoing CT surveillance will have a slightly higher lifetime mortality (598 per 100,000) compared to the mortality from radiation incurred cancer (505 per 100,000). But, lifetime expectancy loss associated with testicular cancer was 83 days--more than three times that associated with radiation-induced cancer (24 days).

Pandharipande told HealthDay News that while it appears the difference may seem small, its actually quite significant when one remembers that this is an average and that some men's life expectancies can be reduced by several years.

The authors argued that the mortality risk from the condition needs to be taken into account when evaluating the future risks of radiation-incurred cancer from medical imaging.

"This must be considered when physicians make imaging decisions for their patients, because the timing of risks changes their relevance," Pandharipande said in a statement. "Risks incurred later in life are not the same as those faced in the present. If you had to choose between the chance of incurring a serious risk now or later in life, most people would choose the latter."

While the current study focused on testicular cancer, the authors said the scenario can be translated into other situations in which CT is needed to help treat a more immediate health risk.

Richard Morin, Ph.D., professor of radiologic physics at the Mayo Clinic in Jacksonville, Fla., told HealthDay the study is important because it actually provides statistics to argue that immediate benefit of treatment outweighs the potential risk of radiation-induced cancer.

"This should be reassuring that an appropriately ordered CT scan has more benefits than risks," Morin said.

To learn more:
- see the abstract in Radiology
- read the announcement
- read the article in HealthDay

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