HG-14 * CLINICAL, RADIOGRAPHIC, AND HISTOLOGIC CHARACTERISTICS OF LONG-TERM SURVIVORS OF DIFFUSE INTRINSIC PONTINE GLIOMA: A REPORT FROM THE INTERNATIONAL DIPG REGISTRY

Abstract

Children with diffuse intrinsic brainstem glioma (DIPG) have a median survival of less than 1 year despite radiation ± chemotherapy. The International DIPG Registry, a collaborative effort among researchers in North America and Australia has enrolled 395 patients with data for over 900 patients committed from 35 institutions. Among the 395 patients, 32 long-term survivors (LTS) (overall survival [OS] ≥2 years) have been identified. Preliminarily, we report clinical, radiographic, and histologic data for 75 of 395 patients, including the 32 LTS and 43 in the comparison (C) group. On central radiographic review, 5 were deemed not to represent DIPG (3 LTS and 2 C). Median age at diagnosis for LTS and C groups was 5.5 and 6.1 years, respectively. Fifty-seven percent of LTS had >6 weeks between onset of symptoms and diagnosis versus 28% for the comparison group (p < 0.05). Incidence of signs and symptoms at diagnosis (cranial nerve, cerebellar, or pyramidal) was similar in both groups. All patients, except 3 LTS, underwent radiation at diagnosis; all but 6 received adjunct chemotherapy. Median OS was 28.4 and 10.8 months for the LTS and C groups, respectively. Two patients (1 LTS) had an H3.3K27M mutation and 2 (1 LTS) had an H3.1K27M mutation. Biology data from 25 other patients from autopsy (n = 12) or biopsy (n = 13) are under analysis. Presence of enhancement on diagnostic imaging was associated with poorer survival (p = 0.02). There was no significant difference in radiographic evidence of hemorrhage, necrosis, diffusion restriction, or tumor size between LTS and C groups. Preliminary data in children with DIPG suggest that LTS have a longer duration of presenting signs and symptoms and less often display radiographic evidence of enhancement at diagnosis. Complete clinical, radiographic, and biology (where available) data on all 395 patients enrolled are currently being analyzed and will be presented.