Background: Traumatic brain injury (TBI) has been reported as a risk factor for the development of brain tumors. However, whether TBI affects systemic cancer remains to be determined. We investigated the incidence and factors associated with cancer development in patients with TBI.
Methods: A propensity score (age, gender, and comorbidity)-matched longitudinal cohort study of 34,556 patients with pre-existing TBI and 69,112 patients without TBI from January 2000 to December 2015 was presented using the Taiwan's National Health Insurance Research Database. The Cox proportional hazard regression model was used to estimate the hazard ratio of developing cancer adjusted by the potential confounding factors. The stratified analysis of age, gender, and comorbidities for each cancer type was evaluated using forest plot analysis.
Results: The cancer incidence rate in the patients with TBI (4.38%) was greater than that in patients without TBI (3.88%). The interval to cancer development in those with TBI (5.65 ± 3.58 years) was shorter than that in those without TBI (6.02 ± 3.65 years). The cancer risk in those with TBI was increased 1.27-fold compared with that in the general population. Of the patients with TBI, age <55 years and male gender indicated a greater incidence of cancer than that of the general population. The patients with TBI had greater cancer frequencies in the head and neck structures compared with those in the general population.
Conclusions: TBI is a risk factor for cancer development, especially in males and those aged <55 years. We hope this information will remind physicians to consider the long-term effects of TBI on cancer development.
Keywords: Age; Cancer; Comorbidity; Gender; Mortality; Traumatic brain injury.
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