Skip the CT Scan if you Can

Breast cancer risk associated with ionizing radiation from medical imaging

(RxWiki News) We're all surrounded by so many things that could potentially cause cancer - what can we do to protect ourselves? To avoid breast cancer, there's one thing a woman needs to do above all else.

Easy to do - just be aware. Unnecessary CT (computed tomography) scans and other medical imaging slightly increases a woman's risk of breast cancer.

"Ask - "Do I really need this X-ay or CT scan?""

The University of California San Francisco (UCSF) has analyzed a report published by the Institute of Medicine (IOM).

Researchers analyzed the major environmental hazards that can up the risk of breast cancer --pesticides, plastics, beauty products and household chemicals.

"Interestingly, none of the consumer products...industrial chemicals...or pesticides..considered could be conclusively linked to an increased risk of breast cancer, although the IOM acknowledged that the available evidence was insufficient to draw firm conclusions for many of these exposures, calling for more research in these areas," the authors wrote.

Two things were associated with an increased risk of breast cancer:

  • Ionizing radiation as delivered through medical imaging from X-rays, CT scans, etc.
  • Postmenopausal hormone replacement with both estrogen and progestin

“The single thing that the IOM highlighted that a woman can do to lower her risk of breast cancer is to avoid unnecessary medical imaging,” said Rebecca Smith-Bindman, MD, professor of radiology and biomedical imaging, epidemiology and biostatistics at UCSF. Dr. Smith-Bindman wrote the article and contributed to the IOM report.

The report states, "The use of CT has increased nearly 5-fold over the last 2 decades. Currently, 75 million CT scans are performed annually in the United States, around half in women, reflecting the large number of individuals who are exposed to this source of radiation."

Most "thought leaders" estimate these numbers overstep the medical need by about 30 percent.

That means women in the United States receive 11,250 too many imaging tests every year.

Benjamin Smith, MD, from The University of Texas MD Anderson Cancer Center, who was not involved in this study, told dailyRx in an email, "Although these tests consistently save countless lives each year, they are not without risk.

"Radiation is well-known to increase risk of all cancers including breast cancer. and thus it is important to limit exposure to ionizing radiation, especially when alternative tests are available," said Dr. Smith who is assistant professor of radiation oncology at MD Anderson.

To be proactive, Dr. Smith-Bindman says that "women need to engage their doctors in the decision-making process and insist on the necessity and safety of all radiological scans they undergo."

Ask lots of questions, including these, Dr. Smith-Bindman suggests:

  • Do we really need to do this to decide the best care for me?
  • What are some alternative tests?
  • Tell me about the safety precautions provided?
  • Will this test change or guide my treatment positively, or can I proceed without the imaging?
  • What about waiting to have a specialist order?

Dr. Smith says, "For those patients who do require diagnostic imaging that will expose them to radiation, it is important to remember that the additional incremental risk of cancer to an individual is very, very small."

That said, the authors conclude, "Computed tomography is a highly valuable tool, but unnecessary use may lead to a small but real increase in a patients' risk of cancer, and patients should be appropriately involved in the decision to undergo imaging."

This research appeared in the Archives of Internal Medicine on June 11, 2012.

No funding information was provided, and the authors made no conflict of interest disclosures.

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Review Date: 
June 18, 2012