Supplementary Material for: A Case for the Worldwide Collection of Primary Benign Brain Tumors

Background: Incidence data on malignant tumors are reported by the International Agency for Research on Cancer, with 189,485 new malignant brain tumors globally in 2002. However, collection and reporting of benign brain tumors are not universal. The objective here is to encourage the collection of primary benign brain tumors worldwide. Methods: Worldwide numbers of primary benign brain tumors were estimated through published articles and cancer registry reports presenting directly or indirectly reported benign incidence rates or frequencies for regions or countries. Results: An estimated 186,678 benign brain tumors were diagnosed worldwide in 2002. The estimated numbers of benign brain tumors were higher in females than males (105,918 vs. 80,759). Since many countries do not report primary benign brain tumors, the incidence rate estimates vary significantly by region. Conclusions: This is the first survey to assess worldwide numbers of benign brain tumors. Under-reporting, non-standardized collection, lack of age-adjustment, and other causes of the varying incidence rates must be considered. However, the estimated number of benign brain tumors approximately equals, and could exceed, the number of malignant brain tumors globally. Registration of primary benign brain histologies in different geographical areas and ethnicities could provide clues to the underlying causes of these tumors.