PO47OVERALL SURVIVAL (OS) IN PATIENTS WITH 1P19Q CO-DELETED WHO GRADE 3 GLIOMAS MATCHES OR EXCEEDS SURVIVAL IN GRADE 2 DISEASE

Abstract

INTRODUCTION: Management of gliomas is becoming increasingly individualised. We evaluated outcomes of patients treated at The Christie NHS Foundation Trust in the era of 1p19q analysis. METHOD: Patients with WHO grade 2 and 3 gliomas referred for 1p19q co-deletion status from 2006-2014 were identified. Clinicopathologic data were collected retrospectively. EORTC low (0-2 risk factors) and high (3-5) risk disease was defined by >40yr, size >6cm, crosses midline, neurologic deficit, no oligodendroglial component. Co-deletion (co-del) was defined as FISH probe ratio ≤0.8 for both chromosomes. RESULTS: 243 patients were identified. Median age 46yr (range 18-83), median follow-up 2.3yr (range 0.5-7.8).151 tumours were WHO grade 2; 88 co-del, 63 non-co-del. Overall, 43% had surgery alone, 42% adjuvant RT, 3% adjuvant chemo, 11% adjuvant chemo-RT, 1 died before. Median survival (MS) & 10yr OS were 13.5yr & 65% and 12.1yr & 63%, respectively. For low versus high risk disease, MS and 10yr OS were 13.5yr & 71% and 6.7yr & 39%, respectively.92 tumours were WHO grade 3; 41 co-del, 51 non-co-del. Overall, 2% had surgery alone, 32% adjuvant RT, 62% adjuvant chemo-RT, 4% died before. Adjuvant chemo-RT was used in 71% co-del and 55% non-co-del, predating definitive guidance. MS & 10yr OS were 12.9yr & 96% and 2yr & 24% for co-del and non-co-del, respectively. On multivariate analysis, co-deletion and WHO PS (p < 0.00002), grade, RT use, chemotherapy use and age (p < 0.01) were statistically significant. CONCLUSION: Outcomes in grade 3 co-deleted patients treated before published conclusive evidence matched or exceeded that in WHO grade 2 disease. These results emphasise the evolving nature of this area and the importance of individualising care.