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Entries in Brain Tumors (2)

Monday
Apr092012

Are Dental X-Rays Causing Brain Tumors?

Stockbyte/Thinkstock(NEW YORK) -- “It’s time for your annual X-rays.”  This is what millions of Americans are told when they visit the dentist.  But new research out of Yale finds dental X-rays may be linked to increased rates of brain tumors.

Meningioma is the most common type of brain tumors that originate in the brain and spinal cord, making up one third of these.  People who were diagnosed with meningioma were compared with healthy individuals.  They were asked how often they had the most common type of dental X-ray, called a bitewing, which involves placing an X-ray film between the teeth and shooting the film from outside of your cheek.  In those who reported having this type of X-ray once a year or more the risk for meningioma was 1.4-1.9 times increased depending on their age.

Another type of dental X-ray, called the Panorex, that rotates around your head taking a picture of all of your teeth from outside your mouth was associated with an almost five-fold increase in rates of meningioma when the X-ray was performed before age 10.  For those older than 10 there was a 2.7 to 3 fold increased risk when this X-ray was performed once a year or more.

Current recommendations by the American Dental Association do admit that there is little use for dental X-rays in healthy people without any symptoms, but still recommends X-rays of healthy children be taken every 1-2 years and every 2-3 years for healthy adults.  The authors think these guidelines may need to be reevaluated in the wake of their findings.

Reactions to the study have been mixed. For critics, the design of the study has some serious flaws. The main weakness is the failure of the researchers to obtain any of the patient’s dental records to verify that the number of X-rays they reported having was true, says Dr. Richard Besser, ABC News' chief health and medical editor.

“People with cancer are more likely to remember having dental X-rays,” explains Besser. “They are searching for some cause of their cancer and may incorrectly attribute it to any number of factors.”  Dr. Besser also points out that the study failed to find any connection between having braces and risk for meningioma.  “When you have braces you remember that clearly, and people who have braces on average undergo more x-rays than people without braces,” says Besser.

Dr. Alan G. Lurie, a Ph.D. radiation biologist who specializes in cancer induction and is president of the American Academy of Oral and Maxillofacial Radiology, agrees with Dr. Besser that the study has a serious flaw.

“They’re asking people to remember (in some cases) a couple of radiographs they had 30 years earlier when they were kids. They’re not going to be able to tell you what kind of X-ray machine was used…what kind of film, were there any retakes?" Lurie says.

Other doctors see this as a strong study and think that it raises valid concerns.  “The current study is well-done and confirms that even in the ‘modern era’ radiation exposure from repeated dental X-rays conveys an increased risk of these tumors,” says Dr. David Schiff of the Neuro-Oncology Center at the University of Virginia.

Overall, doctors are not surprised that dental X-rays could cause this type of tumor because the type of radiation that X-rays give off is known to be associated with brain tumors. “Ionizing radiation is the only well-accepted environmental risk factor for development of meningiomas," says Dr. Schiff.

However they warn that this study cannot prove that dental X-rays cause brain tumors.  It can only reveal a possible association between dental X-rays and tumors.

Still, there are some important things people can do to minimize their exposure to dental X-rays.  For example, patients can ask their doctors whether X-rays are completely necessary, or how much radiation will be delivered by the various options available.

“All health professionals should be thinking that for our patients, each exposure must be beneficial and we should be of a mindset to do the fewest exposures possible to obtain needed diagnostic information," explains Paul Casamassimo DDS, professor and chair of pediatric dentistry at the Ohio State University College of Dentistry and chief of dentistry at Nationwide Children's.

Overall, experts hope that as a result of this study the public gains new awareness of a potential risk and will take their concerns to their dentist.  

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Copyright 2012 ABC News Radio

Thursday
Apr052012

Cellphones and Cancer: Critics Say Kids Risk Brain Tumors

iStockphoto/Thinkstock(NEW YORK) -- Scientists are calling into question a study published last year that failed to find a link between cellphone use and brain tumors in children and teens. They say the study actually shows that cellphone use more than doubles the risk of brain tumors in children and adolescents.

The concerns come from the Environmental Health Trust, a group whose stated mission is to promote awareness of environmental issues they believe are linked to cancer.

In July 2011, the Journal of the National Cancer Institute published the first study on cellphone use and risk of brain tumors in children and adolescents, which was conducted by researchers at the Swiss Tropical and Public Health Institute. The scientists interviewed children and teens in Norway, Denmark, Switzerland and Sweden about their cellphone use and also collected cellphone records for a portion of them. Of the children studied, 350 had been diagnosed with brain cancer and 650 of them were healthy.

The July paper concluded that the data showed no link between cellphone use and brain tumors and "argues against a causal association" between the two.

In a letter published Thursday in the journal, the Environmental Health Trust said the interpretation of the study's results was flawed and contained several statistical errors.

Lloyd Morgan, a senior research fellow at the Environmental Health Trust and one of the authors of the letter, called the study "sloppy" and said the data reported in the original study actually shows that children who used cellphones had a 115-percent increased risk of brain tumors over those who did not.

"There's every indication that this study actually found that children have a doubled risk of brain cancer," Morgan said. "For them to just state that we don't think there's a problem is, for me, quite mystifying."

Messages to the journal and the authors of the original study asking for comment were not returned.

The authors of the original study do note some limitations of their work, including that a relatively small number of children were studied. They also wrote that they could not "rule out the possibility that mobile phones confer a small increase in risk."

International concern over the potential health risks posed by cellphones has gone on for years. In May, the World Health Organization's International Agency for Research on Cancer put the devices in the same category as lead and engine exhaust, citing the possibility that long-term exposure to cellphone radiation could have long-term health effects. Roughly 30 studies so far have failed to draw a conclusive link.

In October, the Environmental Health Trust also criticized the test used by the Federal Communications Commission to measure cellphone radiation, saying the measure did not accurately reflect the radiation transmitted to children and adults while using cellphones.

Concerns over risks to children are particularly heightened, considering the rising use of cellphones among kids and teens and the fear that children's developing brains might be more susceptible to the effects of cellphone radiation.

However, only two studies so far have investigated the link between brain tumors and cellphone use specifically among young people -- one is the disputed study, and the other is a research project currently underway in 13 countries.

Copyright 2012 ABC News Radio







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