Cell phone use has increased dramatically since being introduced in the early 1980s. But its use has raised questions as to whether repeated low-level exposure to radiofrequency (RF) energy can damage human tissue to the point of causing malignancy. Because most users hold the cell phone against their ear, there is concern usage may cause tumors to either the ear (acoustic neuromas), salivary glands, adjacent brain (gliomas), or the tissue lining of the skull (meningiomas).

To address this question, an international study, INTERPHONE, was conducted. The study included users with at least 10 years of exposure. In addition it contained users with the greatest cumulative hours of use of any prior study, making it the largest study to date addressing this controversy. The data analysis was quite extensive, but overall the results indicate that cell phone users did not appear to have an increase in risk of either glioma or meningioma. However, there was a suggestion of an increased risk of glioma for those users who had the highest exposure levels of RF energy. This higher exposure could be from either in an increased number of calls or prolonged calls.