Brain cancer risk factors still remain poorly known, and head trauma has been reported in the literature as a possible one.
A hospital-based case-control study exploring the association between selected risk factors and head injury in adults, brain trauma included, was carried out in a urban area in a developing country. Cases were adults diagnosed with primary brain tumors (n = 231). Controls were matched for gender and age among inpatients hospitalized for various conditions unrelated to brain cancer (n = 261) identified in the same hospitals wherein cases were enrolled.
Risk of having experienced head injury was more frequent among cases (46%) than controls (36%) (ORadj = 1.49; 95% CI = 1.03–2.15). A dose-response effect was observed according to the number of head injury episodes, and a statistically borderline association was observed for meningioma (ORadj = 1.63; 95% CI = 0.96–2.75).
Although recall bias cannot be ruled out, our results suggest an association between prior head injury and the development of brain tumors in adults. It has been suggested that traumatic lesions trigger the effect of other exposures, either by inducing cell proliferation or breaching the blood-brain barrier, resulting in exposure of brain tissue to blood-borne carcinogens. Such hypotheses are reinforced by reports of meningiomas located adjacent to post-traumatic scars. The release of autacoids (such as bradykinin, histamine, and arachidonic acid) in pathological conditions like infection, inflammation, trauma, and hemorrhage is known to modify the blood-brain barrier properties, possibly increasing vascular permeability and allowing diffusion of toxic substances into the brain. Thus, cells damaged by initiators of carcinogenesis would proliferate as a natural result of the trauma, leading to tumor development.
A borderline association between head injury and meningioma (ORadj = 1.63; 95% CI = 0.96–2.75) was observed in this case-control study.