Relationship between the incidence of glioblastoma and natural radiation.

Objectives: To determine the relationship between the impact of high-grade gliomas (HGG) on the population in Córdoba from 2008 to 2019 and the natural radiation background, estimated using radon maps and water origin according to the supply reservoir. Correlation of the results with other prognostic factors. The survival study based on exposure to radon.

Material and methods: Observational, cross-sectional, retrospective 11-year study on 365 patients diagnosed with HGG at the Reina Sofía Hospital in Córdoba, exposed or not, to significant radiation, to estimate the impact that this could have on HGG.

Results: The incidence of patients diagnosed with glioblastoma multiforme (GBM) in those exposed to radon was 41.6 versus 31.4 cases/100,000 inhabitants in those not exposed (p=0.02). The global incidence of HGG was 52.8 cases in those exposed to radon compared with 45 cases/1000 inhabitants in the unexposed ones (p=0.12). It was found that 56.8/100,000 were supplied by reservoirs significant for radon, compared to 31.4 cases/100,000 inhabitants that were not (p=0.23). A Cox regression was performed, leaving IDH mutation and type of intervention in the model: survival is six times higher in positive IDH mutation (p=0.021) and three in surgically intervened (p<0.001).

Conclusions: Long-term exposure to natural radiation does seem to increase the risk factor for the appearance of GBM. However, other factors influencing such exposure must be considered, such as reliable measurements of radiation and time spent in that place.