Distinct demographic profile and molecular markers of primary CNS tumor in 1873 adolescent and young adult patient population

Abstract

We present detailed demographic profile, tumor types, and their molecular markers in adolescent and young adult (AYA) patients of age group between 15 and 39years with primary central nervous system (PCNS) tumors, and compare with pediatric and adult patient populations. Demographic- and disease-related information of 1873 PCNS tumor patients of age 15-39years registered between 1 January 2011 and 31 December 2015 at our institution was analyzed with respect to their demographics and tumor subtypes. Various molecular markers for glial tumors and subgroup classification of medulloblastoma were evaluated for AYA, pediatric, and older adult patient populations. AYA constituted 27% of all PCNS. Median age was 29years. Glial tumors (62.36%) comprised the largest tumor type with astrocytoma (38.55%) being the most common histology. Glioblastoma (51.52%) was the commonest astrocytic tumor with 74.67% of them being isocitrate dehydrogenase 1 (IDH1) negative and 41.38% with O (6)-methylguanine DNA methyltransferase (MGMT) promoter methylated. Diffuse astrocytoma and glioblastoma showed significantly higher IDH1 positivity and loss of alpha-thalassemia/mental retardation syndrome X-linked (ATRX) for AYAs as compared to pediatric and adult patient populations (p < 0.0001). Medulloblastoma (73.8%) was the most commonly diagnosed embryonal tumor, with sonic hedgehog (SHH) being the commonest molecular subtype (48%). Younger patients among AYA population presents with pediatric type of tumor spectrum, while older ones present with more aggressive tumor subtypes. This is among the few studies reporting spectrum of PCNS tumor in AYA population with distinct tumor subtypes and molecular profiles. AYA patient populations may need special attention with appropriately designed clinical trials.