Epidemiological Trends of Histopathologically WHO Classified CNS Tumors in Developing Countries: Systematic Review

Background: Many developing countries are lagging behind in reporting epidemiological data for individualcentral nervous system (CNS) tumors. This paper aimed to elicit patterns for the epidemiology of individualWorld Health Organization (WHO) classified CNS tumors in countries registered by WHO as “developing”.Materials and
Methods: Cyber search was carried out through 66 cancer networks/registries and 181 PubMedpublished papers that reported counts of CNS tumors for the period of 2009-2012. The relationship betweenthe natural log of incidence Age Standardized Rate (ASR) reported by Globocan and Latitude/ Longitude wasinvestigated.
Results: Registries for 21 countries displayed information related to CNS tumors. In contrast tendsfor classified CNS tumor cases were identified for 38 countries via 181 PubMed publications. Extracted datashowed a majority of unclassified reported cases [PubMed (38 countries, 45.7%), registries (21 countries, 96.1%)].For classified tumors, astrocytic tumors were the most frequently reported type [PubMed (38 countries, 1,245cases, 15.7%), registries (21 countries, 627 cases, 1.99%]. A significant linear regression relationship emergedbetween latitudes and reported cases of CNS tumors.
Conclusions: Previously unreported trends of frequenciesfor individually classified CNS tumors were elucidated and a possible link of CNS tumors occurrence withgeographical location emerged.