HELSINKI, December 19, 2011 ― There is ongoing discussion about whether use of cell phones leads to an increase in the rate of brain cancer, and the public is seeking answers.
Is there an increase in the number of cases of brain cancer in the population over the last several years? What is the individual cellphone user's risk? What are the risks for society as a whole?
These are important questions. Based on the current science, following are the best answers:
Is there an increase in brain cancer cases in the Scandinavian populace?
Scandinavian countries, not without the reason, pride themselves for the best cancer registries in the world. The Cancer Registry in Finland, my home country, provides insights into the number of brain cancer cases among the Finns.
The graph presented above, which has been generated by the Finnish Cancer Registry, shows a steady increase in brain and nervous system cancer cases among Finnish women and, to a lesser extent, among Finnish men.
Therefore, the "urban legend" that there has been no increase in brain cancer cases in recent years should be put to rest. Of course there may be country-to-country differences. For example, news programs have recently discussed a steady increase in brain cancer cases in
While the data demonstrate an increased incidence of brain cancer in some countries, we should remain cautious and not jump to the easy conclusion that cell phone radiation is responsible. Cell phone radiation may be the cause for the increase, but there have been other changes to the way we live and our environment, and so it might not be.
Unfortunately, the two largest epidemiology studies, the Interphone and the Danish Cohort, designed to provide us with the necessary information on the link between cell phone radiation and brain cancer have serious design flaws, making their findings uncertain.
If we assume, as some studies suggest, that cell phone radiation causes cancer, then the second question is: What is the cancer risk for the individual cell phone user?
If we look at the results of the Interphone study as published, without the interpretation provided by the authors, the data suggest that talking on mobile phone for 30 minutes per day for 10 years might increase the risk of the brain cancer 1.4-fold, that is, by 40%.
Studies from the Swedish group of Hardell and co-workers show the highest risk of brain cancer among the persons who used cell phones longer than ten years. For that group, the risk increases 2.7-fold, or by 170%.
How do these increases translate into potential cancer cases using statistics from the Finnish Cancer Registry?
The latest published statistics of cancers of the brain and central nervous system says that in Finnish men, the age-adjusted rate of brain cancer for years 2005-2007 is 11.2 cases/100,000 and the rate for Finnish women is 13.3 cases/100,000.
The Interphone study indicating a 40% increase would bring these numbers for men and for women to 15.7/100,000 and 18.6/100,000, respectively.
The Hardell and co-workers study indicating 170% increase would bring these numbers for men and for women to 30.2/100,000 and 35.9/100,000, respectively.
So, in both cases, the increase of the individual risk is not very high and brain cancer remains a rare disease.
The last question is, how would the increase of brain cancer cases impact society?
From the viewpoint of society, the financial burden caused by the additional cancer cases (costs of medical treatment, lost productivity, monetary and non-monetary burden for the families) could be significant.
According to the Finnish Cancer Registry, the number of newly diagnosed brain and central nervous system cancer cases in 2007 was 372 in men and 561 in women.
A 40% increase would mean that there would be an additional 149 cases among the Finnish men (total of 521 cases) and an additional 224 cases among the Finnish women (total of 785 cases). That means an additional burden of 373 brain cancer cases for the health system and the families.
A 170% increase would mean that there would be an additional 632 cases among the Finnish men (total of 1004 cases) and an additional 953 cases among the Finnish women (total of 1515 cases). It means that there would be an additional burden of 1585 brain cancer cases for the health system.
The population of Finland is approximately 5.4 million. To put things in a better perspective: the population of
It all means that the burden for the society might be sizable, if it materializes.
However, the Interphone and Hardell and co-workers studies require independent confirmation. The major problem in both studies is that the number of cell phone users who used phones for more than ten years was relatively low. This makes statistical evaluation uncertain.
Take home message: Individual risk is relatively small, but the risk for the society might be costly.
Therefore, before we know more, it is better to use precaution and limit exposures to cell phone radiation by:
- limiting the non-essential cell phone use by the children,
- using landlines whenever possible, especially for longer calls,
- limiting the length of cell phone calls,
- texting whenever possible,
- using the speakerphone function,
- using earphones
- keeping cell phones out of the pockets.
Read more from Dariusz Leszczynski in his science blog “BRHP - Between a Rock and a Hard Place” at http://betweenrockandhardplace.wordpress.com Dariusz is a Research Professor at the Radiation and Nuclear Safety Authority in Finland.
Follow Dariusz on twitter: @blogBRHP
Disclaimer: the opinions presented in this column are author's own and should NOT be considered as the official opinions of the STUK - Radiation and Nuclear Safety Authority in Finland.
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