Patterns of care and treatment outcomes in older adults with low grade glioma: a 50-year experience

Abstract

The purpose of this study was to identify changes in presentation, treatment and outcomes of older patients with low-grade glioma (LGG) over the past 50 years. 94 adults aged 55 or older upon diagnosis of a WHO grade II LGG at Mayo Clinic between 1960 and 2011 were included and grouped by those diagnosed before (group I: 1960-1989) and after (group II: 1990-2011) the routine use of post-operative MRI. Median follow-up was 11.4years. Pathologic diagnoses included astrocytoma in 55%, mixed oligoastrocytoma in 18% and oligodendroglioma in 27%. Gross total resection (GTR) was achieved in 10%, radical subtotal resection (rSTR) in 6%, subtotal resection (STR) in 20% and biopsy only in 64%. Post-operative radiotherapy (PORT) was given in 77%. More patients in the modern era received GTR/rSTR (20 vs. 7%), though the difference was not statistically significant. Median progression-free survival (PFS) was 3.0 years, with 5- and 10-year PFS rates of 31 and 10%, respectively. Median, 5- and 10-year overall survival (OS) was 4.1years, 43 and 17%, respectively. PFS and OS did not improve in the modern era. Factors negatively associated with PFS on multivariate analysis included astrocytoma histology, contrast enhancement and STR/biopsy. Factors associated with poor OS on multivariate analysis included astrocytoma histology, deep location, contrast enhancement and STR/biopsy. Despite reports of improving outcomes for younger patients treated in the modern era, outcomes have not significantly improved for older patients. Further efforts to improve outcomes based on molecular genotyping are needed to determine a rational strategy for treatment intensification.