Abstract Infant-type hemispheric glioma (IHG) is newly recognized in the fifth edition of the World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS). Diagnosed during infancy, these large hemorrhagic gliomas commonly harbor structural rearrangements in receptor tyrosine kinases (RTKs) and have a distinct methylation profile. Due to the novelty and rarity of IHG, optimal treatment and factors determining clinical outcomes are yet to be established. Here, we curated 164 IHG cases; 155 identified by methodical literature search and 9 new cases collected from collaborators. All tumors were hemispheric in location, were diagnosed at a median age of 3 (0-52) months, and were frequently (95%) non-metastatic. 95% cases reported fusions in RTKs (ALK 45%, NTRK1/2/321.5%, ROS119.5%, MET 8.5% and ABL2 0.5%). 64%, 20%, and 8% of patients were treated with surgery + adjuvant chemotherapy, surgery-only and surgery + targeted therapy (TT), respectively. 3-year event free survival (EFS) and overall survival (OS) was 47.9% 39.1-58.7 and 79.8% 72.4-88.0. Only 5 patients received radiation during their treatment course. Twenty-three patients succumbed to disease, of which tumor progression (52%) and intra-cranial hemorrhage (26%) were the most common causes of death. In multivariate analysis, presence of residual tumor significantly increased the risk of death (p 0.05); 3-year EFS for patients with versus without residual disease was 33.5% versus 54.8% (p 0.05);3-year OS was 62.8% versus 94.0% (p 0.05). Patients treated with surgery-only also showed comparatively worse 3-Y- EFS 31.2% (p 0.05). In conclusion, IHG is a fusion driven tumor, complete surgical resection is associated with a better prognosis and, paradoxically, children die from intracranial hemorrhage (likely surgically induced trauma). Furthermore, we identified a sizeable gap between EFS and OS. Together, these findings show that patients can survive progression and suggest that optimal primary therapy for IHG has not been established.
Bagchi et al. (Fri,) studied this question.