Table I.

Exclusions due to non-differentiation between low grade and high-grade tumors.

Author, year	Histology	ICD-O code	Refs.
Ostrom et al, 2013	Oligoastrocytic tumors	9382	(4)
Dolecek et al, 2009	Oligoastrocytic tumors	9382	(5)
Gittleman et al, 2015	Oligoastrocytic tumors	9382	(10)
Ostrom et al, 2013	Pineal tumors	9360, 9361, 9362	(4)
Dolecek et al, 2009	Pineal tumors	9360, 9361, 9362	(5)
Ostrom et al, 2013	Ependymal tumors	9383, 9391, 9392, 9393, 9394	(4)
Dolecek et al, 2009	Ependymal tumors	9383, 9391, 9392, 9393, 9394	(5)
Gittleman et al, 2015	Ependymal tumors	NA	(10)
Dobec-Meić et al, 2006	Ependymal tumors	NA	(11)
Ostrom et al, 2013	Neuronal and mixed neuronal-glial tumors	8680, 8681, 8690, 8693, 9412, 9413, 9442, 9492, 9493, 9505, 9506, 9522, 9523	(4)
Dolecek et al, 2009	Neuronal and mixed neuronal-glial tumors	8680, 8681, 8690, 8693, 9412, 9413, 9442, 9492, 9493, 9505, 9506, 9522, 9524	(5)
Ostrom et al, 2013	Choroid plexus tumors	9390	(4)
Dolecek et al, 2009	Choroid plexus tumors	9390	(5)
Ostrom et al, 2013	Meningioma	9530, 9531, 9532, 9533, 9534, 9537, 9538, 9539	(4)
Dolecek et al, 2009	Meningioma	9530, 9531, 9532, 9533, 9534, 9537, 9538, 9539	(5)

NA, information not available; ICD-O, international classification of diseases of oncology; Refs, reference number.