Naturopathic Fun Facts
By Sarah LoBisco, ND
Below are some recent summaries on the latest findings in diagnostic tests and health risks. My June 2012 Top Reads on my home page explains more....
CT Scans in Children Increase Risk for Leukemia
Use of CT scans in children to deliver cumulative doses of about 50 mGy might almost triple the risk of leukaemia and doses of about 60 mGy might triple the risk of brain cancer. Because these cancers are relatively rare, the cumulative absolute risks are small: in the 10 years after the first scan for patients younger than 10 years, one excess case of leukaemia and one excess case of brain tumour per 10 000 head CT scans is estimated to occur. Nevertheless, although clinical benefits should outweigh the small absolute risks, radiation doses from CT scans ought to be kept as low as possible and alternative procedures, which do not involve ionising radiation, should be considered if appropriate.
Pearce, M. et al.Radiation exposure from CT scans in childhood and subsequent risk of leukaemia and brain tumours: a retrospective cohort study. The Lancet, Early Online Publication, 7 June 2012. doi:10.1016/S0140-6736(12)60815-0
Diagnostic Imaging Use Increases
During the 15-year study period, enrollees underwent a total of 30.9 million imaging examinations (25.8 million person-years), reflecting 1.18 tests (95% CI, 1.17-1.19) per person per year, of which 35% were for advanced diagnostic imaging (computed tomography [CT], magnetic resonance imaging [MRI], nuclear medicine, and ultrasound). Use of advanced diagnostic imaging increased from 1996 to 2010; CT examinations increased from 52 per 1000 enrollees in 1996 to 149 per 1000 in 2010, 7.8% annual increase (95% CI, 5.8%-9.8%); MRI use increased from 17 to 65 per 1000 enrollees, 10% annual growth (95% CI, 3.3%-16.5%); and ultrasound rates increased from 134 to 230 per 1000 enrollees, 3.9% annual growth (95% CI, 3.0%-4.9%). Although nuclear medicine use decreased from 32 to 21 per 1000 enrollees, 3% annual decline (95% CI, 7.7% decline to 1.3% increase), PET imaging rates increased after 2004 from 0.24 to 3.6 per 1000 enrollees, 57% annual growth. Although imaging use increased within all health systems, the adoption of different modalities for anatomic area assessment varied. Increased use of CT between 1996 and 2010 resulted in increased radiation exposure for enrollees, with a doubling in the mean per capita effective dose (1.2 mSv vs 2.3 mSv) and the proportion of enrollees who received high (>20-50 mSv) exposure (1.2% vs 2.5%) and very high (>50 mSv) annual radiation exposure (0.6% vs 1.4%). By 2010, 6.8% of enrollees who underwent imaging received high annual radiation exposure (>20-50 mSv) and 3.9% received very high annual exposure (>50 mSv).
Conclusion Within integrated health care systems, there was a large increase in the rate of advanced diagnostic imaging and associated radiation exposure between 1996 and 2010.
Rebecca Smith-Bindman, et al. Use of Diagnostic Imaging Studies and
Associated Radiation Exposure for Patients Enrolled in Large Integrated Health
Care Systems, 1996-2010. JAMA. June 13, 2012, Vol 307, No. 22. http://jama.jamanetwork.com/article.aspx?articleid=1182858
Safer Pediatric Radiation Guidelines in Order
May 18, 2012 -- The realization that 1-size-fits-all radiography can be bad for children has forged a coalition between federal regulators, physicians, physicists, and medical device manufacturers to make medical imaging involving exposure to ionizing radiation safer for young patients.
The US Food and Drug Administration (FDA) took action May 9 as part of this collaboration by releasing proposed guidance encouraging manufacturers to consider the safety of children in the design of new X-ray imaging devices. The federal agency recommended equipment features that would alter the performance of X-ray imaging devices designed for general clinical use to address the specific requirements of younger patients.
Brice, J. FDA Proposal Aims at Lower Doses for Pediatric X-Ray. Medscape. May 18,
PSA and Mammograms (Mercola)
- The United States Preventive Services Task Force (USPSTF) has given the prostate-specific antigen test (PSA test) a "D" rating, meaning that "there is moderate or high certainty that the service has no net benefit or that the harms outweigh the benefits"
- The screening is no longer recommended as a routine test for men of any age, following a review of research that shows only zero to one out of every 1,000 men who are screened would actually benefit from the exam, while many others would suffer from the side effects of unnecessary treatments, ranging from impotence to death
- USPSTF is not suggesting the PSA screening never be used, just that it shouldn't be offered to every man at his yearly visit; the test would still be available as individual cases dictate, such as if a man is symptomatic or has a very high risk of aggressive prostate cancer
· Reuters reported:
"If a biopsy finds seemingly malignant cells, as happens to 120 in 1,000 screened men, about 90 percent of men opt for surgery, radiation or hormone-deprivation therapy. Up to five men in 1,000 opting for surgery will die within a month of the operation; 10 to 70 more will have serious cardiovascular complications such as a stroke or heart attack. After radiotherapy and surgery, 200 to 300 of 1,000 men suffer incontinence, impotence or both. Hormone-deprivation therapy causes erectile dysfunction in about 400 of 1,000 men."
· In many ways, mammograms are the equivalent of the PSA test for women. In 2009, revised mammogram guidelines were issued by the USPSTF, which found that the benefits of mammogram screening do not outweigh the risks for women under the age of 50. Therefore, they recommend that women wait to get regular screenings until the age of 50, and only get one every other year thereafter. This caused a backlash from women and doctors who felt their "life-saving" screening tool was being taken away, and certain public health agencies, like the American Cancer Society, did not modify their recommendations and still recommend yearly mammograms starting at 40.
Mercola, J. Could Your Annual Doctor's Visit Cause More Harm Than Good. mercola.com. June 23, 2012. http://articles.mercola.com/sites/articles/archive/2012/06/23/prostate-screening-negative-effects.aspx?e_cid=20120623_DNL_art_2