Grouping methods
astrocytoma, Tumor, C71.6
PILOCYTIC ASTROCYTOMA, ASTROCYTOMA, TUMOR
For a more intuitive and standardized study, the study data were transformed into dichotomous or multi-categorical variables. Age was classified into five age groups: < 20, 20–39, 40–59, 60–79, and ≥ 80; Race into black, white, and others; and Histological type into five categories: diffuse astrocytoma, anaplastic astrocytoma, pilocytic astrocytoma, unique astrocytoma variants, and astrocytoma, NOS. The Primary site was divided into brain (C71.0–C71.5), cerebellum (C71.6), brainstem (C71.7), spinal cord (C72.0), and others (C70.0 71.8 C71.9 C72.3 C72.5 C72.8 C75.1 C75.3); the Lateral division was unilateral and bilateral; the Grade was I-IV; for continuous variable Tumor size and Extension were divided using X-tile to select the best grouping method, and finally the Tumor size was classified as ≤ 60 mm and ≥ 61 mm, and the Extension was classified as 10–30 mm and 40–75 mm; Surgery, Radiation, Chemotherapy: yes/no; Tumor number was grouped as 1 and > 1.