Frontal & temporal lobe gliobastoma incidence increased in the US from 1992-2006
This 2012 study examined trends in brain cancer incidence in the U.S. from 1992 to 2006. The data was derived from three population-based cancer registries: the National Cancer Institute’s SEER program which collects cancer data from nine states, the California Cancer Registry, and the Los Angeles Cancer Surveillance Program.
Glioma is a tumor that develops in the glial cells which support the neurons in the brain. The disease accounts for 80% of all brain cancers. Glioblastoma multiforme (GBM) is the most common and most aggressive form of glioma. With state-of-the-art treatment the median survival time for a patient with GBM is 15 months but less than 5 months if untreated.
Although across all three cancer registries, the study reported that the average age-adjusted incidence rates for all gliomas decreased from 0.5% to 0.8% annually, glioma incidence increased in the frontal lobes 1.4% to 1.7% annually and in the temporal lobes 0.5% to 0.9% annually from 1992 to 2006.
The average age-adjusted incidence rates for GBM incidence increased in the frontal lobes 2.4% to 3.0% annually and in the temporal lobes1.3% to 2.3% annually.
The authors concluded, “Although these results may represent an effect of diagnostic bias or refinements in anatomical subsite coding, an environmental cause of the increases of high grade frontal and temporal lobe malignancies cannot be ruled out. Further studies are indicated to establish whether a correlation with environmental factors exists.” (p. 524)
The graphs for overall glioma incidence by anatomical location by year appear in Figure 1 and GBM incidence in Figure 2. Although there is annual variability, it appears to me that the upward trend in frontal and temporal lobe glioma and GBM incidence increased around 2001-2002. This is consistent with the increasing use of cordless phones as well as cell phones by the population. Hardell’s case-control research on mobile phone use and brain cancer suggests that cordless phone use may be as harmful as cell phone use, and that tumors are more likely to occur in the frontal and temporal lobes than in other parts of the brain.