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Radiofrequency Radiation: A Possible Carcinogen

 

One of the functions of the International Agency for Research on Cancer (IARC) of the World Health Organization (WHO) is to identify and classify various substances and agents for their carcinogenic potential.

 

In 2011 a multidisciplinary IARC Working Group classified radiofrequency (RF) radiation emitted by mobile phones as "possibly carcinogenic to humans" (category 2B).

 

Following the conclusions of the IARC Working Group, Dr. Christopher Wild, Director of the IARC, stated that "Given the potential consequences for public health of this classification and findings, it is important that additional research be conducted into the long‐term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands‐free devices or texting. "

 

This classification implies that until conclusive proof is obtained regarding the presence or absence of a relationship between radiofrequency radiation and the risk of developing cancer, mobile phones and other non-ionizing radiation-emitting technologies should be used judiciously.

 

 

Since the dawn of time humans have been exposed to natural sources of non-ionizing radiation.  However, advances in technology, and, in particular, the development of many communications devices since the mid-1990s, have increased this exposure and its sources considerably.  At the same time, concern over possible effects of non-ionizing radiation on human health increased.  As a consequence, comprehensive research is being conducted in an effort to determine the safety of using non-ionizing radiation-emitting devices.

 

What are carcinogens?

Cancer is caused by alterations in the genetic material (DNA) of the cell.  Some of these changes are inherited from one's parents, while others are produced by exposure to extraneous factors (also termed environmental factors).  Substances and modes of exposure that may cause cancer are known as carcinogens.

Environmental agents that may provoke the initiation of cancer and other diseases include, for example:

  • Lifestyle factors (nutrition, smoking, etc.)
  • Natural factors (physical, such as ultraviolet light from the sun or radon, or biological, such as viruses or endogenic hormones).
  • Medical applications (such as chemotherapy, radiotherapy, immune-depressants, exogenous hormones, or exposure to diagnostic radiation).
  • Air pollution
  • Occupational factors (i.e. originating in the workplace, such as certain chemicals).

Carcinogens do not all have the same potential for causing cancer, and they do not necessarily always cause cancer at every exposure.  Some will cause cancer only at high levels of exposure or prolonged exposure.  Also, the potential for developing cancer differs from one individual to another, depending on a number of factors, such as type, duration and intensity of exposure, and the genetic constitution of the individual.

 

Who defines carcinogens and what determines the risk level of a carcinogen?

There are a number of agencies and organizations whose function is to identify and classify the carcinogenic potential of various substances and factors.  One of these is the International Agency for Research on Cancer (IARC), established by the World Health Organization (WHO) in 1965, as a scientific branch for research on cancer.  The aims of this agency (today comprising 22 countries) are to promote research towards understanding the causes of cancer, and to advance the means to prevent and reduce cancer morbidity.

 

IARC publishes comprehensive reviews (monographs) summarizing the research on the effects of environmental factors that may increase the risk of developing cancer in humans.  This information is used by health authorities in countries around the world, to assist them in policy-making regarding the prevention of exposure to carcinogenic agents.

 

The reviews are conducted by multidisciplinary working groups of expert scientists from different countries.  The groups review the accumulated up-to-date published scientific information on a specific agent, and classify it under one of 5 categories according to its carcinogenic potential in humans:

 

Group 1: Carcinogenic to humans

 

Group 2A: Probably carcinogenic to humans

 

Group 2B: Possibly carcinogenic to humans

 

Group 3: Not classifiable as to its carcinogenicity to humans

 

Group 4: Probably not carcinogenic to humans

The decision regarding the relationship between radiofrequency radiation and the risk of developing cancer

In May 2011 an IARC Working Group convened in Lyon, France, to assess the carcinogenicity of radiofrequency electromagnetic fields (RF-EMF).  The group comprised 31 scientists from 14 countries.  The evaluation was based on population studies and research on experimental animals. Most of these studies were conducted after the early 1990s, when the use of radiofrequency-emitting technologies began to increase.  Studies on occupational exposure to radar and microwaves, environmental exposure associated with radio, TV and wireless transmission, and individual exposure associated with the use of mobile phones, were reviewed.

 

The IARC Working Group stated that there was limited evidence regarding the increased risk of developing malignant brain tumors (glioma) and benign tumors of the auditory nerve (acoustic neuroma) among mobile phones users.  The Working Group also pointed out that the evidence was insufficient to draw conclusions regarding other types of cancer and/or regarding occupational and environmental exposure.  The Working Group did not quantitate the risk; however, one study of past cell phone use (up to the year 2004), showed a 40% increased risk for gliomas in the highest category of heavy users (reported average: 30 minutes per day over a 10‐year period).  On the basis of this conclusion, the Working Group classified radiofrequency radiation emitted from mobile phones in the 2B category: "possibly carcinogenic to humans".

 

Following the conclusions of the IARC Working Group, Dr. Christopher Wild, Director of the IARC, stated that "Given the potential consequences for public health of this classification and findings, it is important that additional research be conducted into the long‐term, heavy use of mobile phones. Pending the availability of such information, it is important to take pragmatic measures to reduce exposure such as hands‐free devices or texting."

 

Why is it so difficult to determine whether radiofrequency radiation is carcinogenic?

Despite the numerous studies conducted on this topic at all levels of research, no unequivocal conclusion can be reached as yet, regarding a possible link between exposure to radiofrequency radiation and the risk for developing cancer.  This is due to fundamental problems in research on this topic, including methodological problems and the difficulty of assessing mobile phone exposure levels.  Moreover, most studies were performed on adult populations, and were conducted at a time when the use of mobile phones was relatively new.  For instance, in the INTERPHONE study mentioned in the IARC report, comprising data collected up to 2004, only 11% of users reached 10 years of use.  Also, the extent of mobile phone use in this study was low, compared to usage today.  The median time for mobile phone use was only about 2- 2.5 hours/month, and the average duration of accumulated use among the group classified in the upper 10% of users, was 27 minutes/day. 

 

 It is important to note that a long time lapse (latency period) is generally observed between exposure to a carcinogen and the appearance of cancer, especially brain tumors.  Therefore, in order to assess a possible causal relationship between exposure and tumor development, studies should consider this long latency period between the exposure and the outcome.

 

What does the classification signify?

The classification implies that until unequivocal evidence is provided regarding the presence or absence of a causal relationship between radiofrequency radiation and cancer development, mobile phones and other non-ionizing radiation-emitting technologies should be used judiciously.  Considering the vast numbers of individuals exposed to cellular technology in all sectors of the population (including children) the policy of the TNUDA center, in accordance with that of many other countries, is to act according to the precautionary principle. This implies taking precautionary measures to reduce exposure, even if the causal relationship between the agent and damage has not been proven scientifically.

 

For the IARC monograph on radiofrequency electromagnetic fields click here  

 

A brief summary of the IARC Working Group monograph was published in the eminent scientific journal Lancet Oncology in June 2011.

 

 

References

 

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