Epidemiological study of brain cancer in Iran: A systematic review

Introduction: In recent decades, the incidence and mortality rate of brain tumours, especially in adults, has increased. In order to better plan to reduce the burden of this cancer, knowledge of the epidemiological aspects of this disease is essential. Therefore, due to the lack of a comprehensive study on brain cancer in Iran, this study aimed to investigate the epidemiological aspects of this cancer in Iran. Methods: In June 2020, keywords of 'brain tumour', 'nervous system tumours', 'nervous system neoplasm', 'nervous system cancer', 'central nervous system (CNS)' and 'Iran' were searched on Medline/PubMed and Web of Science databases Scopus, Embase, SID, IranMedex, and Google Scholar. The search results were entered Endnotes Version 8; finally, 35 full papers were reviewed and included in the study. Results: The incidence of brain cancer and CNS tumour is lower in children in central Iran. The incidence of CNS cancer was relatively high among children in Golestan province. Furthermore, the standardised incidence of primary CNS tumours in Iran is 5.69 per 100,000, which is lower than in other countries. Nervous system malignancies were more common in men than in women (age-standardized rate 3 versus 2.2 per 100,000 in men and women, respectively). Tehran had the highest incidence of CNS tumours. Meningiomas were the only most common tumour in women. Gliomas were the most common primary brain tumour, and most of the lesions in this subgroup were in low-grade astrocytoma and ependymomas. Brain cancer mortality was higher in men than in women. Age is a potential risk factor, and the incidence of CNS tumours increases with increasing age after 30 years. Conclusion: Nervous system cancers are on the rise in Iran due to lifestyle changes and increased risk factors. Planning to reduce risk factors and early detection of the disease can be helpful in reducing cases and reducing mortality.