In a review of eight different studies, there were no statistically significant positive associations with cumulative call time and brain cancers.
Methodological issues limit the conclusions that can be drawn from the study, the researchers conclude, but its results, along with those from other epidemiological, biological and animal studies suggest that within about 10 years to 15 years after first use of mobile phones there is unlikely to be a material increase in the risk of brain tumors in adults. Data for childhood tumors and for periods beyond 15 years are currently lacking.