Inskip PD, Hoover RN, Devesa SS. Brain cancer incidence trends in relation to cellular telephone use in the United States. Neuro Oncol. Jul 16, 2010 Ahead of print.
In the United States, mobile phones were first used in 1980’s, became widespread in the mid-to late 1990’s and in the recent years its use is “pervasive”. If brain cancer risk is associated with mobile phone use, one might expect changes in brain cancer incidence rates over time. There are some reports of increasing trends in brain cancer rates in recent years. However, data from some national cancer registries and from the Surveillance, Epidemiology and End Results (SEER) Program of the U.S. National Cancer Institute indicate stable or even declining rates over the relevant time period.
The objective of this study was to examine temporal trends in brain cancer incidence rates in the U.S. in more details, including trends by age and location of cancer in the brain.
The authors used data collected by the SEER program on brain cancers diagnosed in white patients during 1977-2006. The data used in this study covered about 10% of the US population. Age-specific and age-adjusted incidence rates were calculated separately for males and females. Trends in brain cancer incidence rates for 1977-1991 and for 1992-2006 were analyzed separately. The earlier time period precedes the widespread use of mobile phones. By the end of this period, computed tomography (CT) and magnetic resonance imaging (MRI) had become widely available making diagnostic accuracy less of an issue. The latter time interval is relevant to the mobile phone use. Consideration of the longer term pattern in brain cancer rates would help in the interpretation of the more recent data.
There was a highly significant increasing trend in 1977-1991 for brain cancer among people under 30 and those over 65 years of age, attributable largely to the increase in diagnostic accuracy due to introduction of CT and MRI. The trends in age-specific rates for the period 1992-2006 were either downward or flat except the 20-29 year age group. In this age group, there was a statistically significant increase in brain cancer incidence rates for women, but no such trend was observed for men. The increasing trend in 20-29 year old women was due to tumors in the frontal lobe of the brain. There was no such trend for tumors in the temporal or parietal lobes, the parts of the brain most heavily exposed to radiofrequency radiation from mobile phones.
Interpretation and Conclusion
The results of this study based on high-quality cancer incidence data do not support the hypothesis that mobile phone use causes brain cancer. However, if brain cancer risk is increased only in long-term users and/or the induction period is long, it may be too early for any effect to be seen in general population incidence rates.