Central nervous system (CNS) neoplasms are relatively uncommon and potentially debilitating. From 1984-2012, there were around 200 new cases of malignant primary brain tumours each year in Hong Kong, and the trend has been static. To improve epidemiological reporting of CNS tumours in Hong Kong, the Hong Kong Cancer Registry (HKCaR) has established the brain and CNS tumour registry (BCTR) to collect all incident cases of primary malignant and non-malignant CNS tumours since 2013.
The HKCaR is a population-based cancer registry in Hong Kong. Clinical records and pathology reports were obtained from public and private care providers with high coverage of 95%. These records were entered, cleansed and validated. Incidence of pathologically or clinically diagnosed CNS tumours with malignant, benign or uncertain behaviours were reported over the period of 2013-2017. The incidence were age-standardized with the 2000 US standard population and compared with US data from CBTRUS.
The age-standardised incidence of malignant and non-malignant brain tumours pooled over the period of 2013 to 2017 were 3/100,000 population and 8.6/100,000 population respectively. The top three most common types of malignant neoplasms were glioblastoma, other glial tumours and embryonal tumours; and in non-malignant neoplasms being meningioma, pituitary tumours and nerve sheath tumours. The incidence of both malignant and non-malignant tumours were around half of that in the US (7.08 and 16.33 per 100,000 population in the period of 2012-2016). The incidence of non-malignant and malignant brain tumours both increases significantly with age, with steep increment for non-malignant tumours starting from age of 45-64 and for malignant after the year of 65. The incidence rate in the whole population and in each age group has remained static over the reported years.
Significant geographical differences in incidence of CNS tumours was observed between Hong Kong and the US. Under-diagnosis of brain tumour is unlikely due to easy access to public healthcare service and cross sectional imaging. The difference may be due to ethnic and environmental factors, which include higher rate of allergic conditions in Hong Kong which may confer protection. Further investigations are warranted.
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