Genomic Analysis, Surgical Treatment and Outcomes of Lower-Grade Gliomas in a Single Institution

Abstract

Recent research has demonstrated that IDH and 1p/19q status in lower grade tumours better predicts clinical outcome than histological class. We reviewed our institutional outcomes based on these parameters combined with the addition of the outcomes of biopsy versus resection. Design A 10-year retrospective case review analysing histological grade and genetics of tumour specimens, surgical treatment and resulting clinical outcomes. Patients undergoing biopsy or resection of lower grade gliomas between 2005 and 2016 in our institution. Cases were identified from histology database records. Data was then collected using case notes, operation reports and PACS. 147 patients underwent sampling of a tumour on which genetic analysis was performed. 48 had biopsy alone, 99 underwent resection. Histologically 63 cases were classified as Grade II, 84 as Grade III. IDH mutation was present in 74, of which 84% survive, and negative in 41 of which 49% survive giving a RR of 1.53 (p-value 0.0002). Classic 1p/19q co-deletion was present in 41 of which 78% survive, and absent in 69, of which 72% survive giving an insignificant (p-value 0.1695) increased survival of 1.18. To date our outcomes appear to be consistent with those published in the literature. Genetic analysis of historical samples is important to understand the behaviour of lower grade gliomas.