Background: To identify changes in patient presentation, treatment, and outcomes of low-grade gliomas (LGGs) over the past 50 years.
Methods: Records of 852 adults who received a diagnosis at Mayo Clinic from 1960 through 2011 with World Health Organization grade II LGGs were reviewed and grouped by those who received a diagnosis before (group I: 1960-1989) and after (group II: 1990-2011) the routine use of postoperative MRI.
Results: Median follow-up was 23.3 and 8.7 years for groups I and II, respectively. Patients in group I more often presented with seizures, headaches, sensory/motor impairment, and astrocytoma histology. Over time, more gross total resections (GTRs) were achieved, fewer patients received postoperative radiotherapy (PORT), and more received chemotherapy. Median progression-free survival (PFS) and overall survival (OS) were 4.4 and 8.0 years, respectively. Although PFS was similar, 10-year OS was better in group II (47%) than in group I (33%; P < .0001). Improved PFS in multivariate analysis was associated with group I patients, nonastrocytoma histology, small tumor size, successful GTR, or radical subtotal resection (rSTR), PORT, and postoperative chemotherapy. Factors associated with improved OS in multivariate analysis were younger age, nonastrocytoma histology, small tumor size, and GTR/rSTR.
Conclusions: OS for LGG has improved over the past 50 years, despite similar rates of progression. In the modern cohort, more patients are receiving a diagnosis of oligodendroglioma and are undergoing extensive resections, both of which are associated with improvements in OS. Because of risk factor stratification by clinicians, the use of PORT has decreased and is primarily being used to treat high-risk tumors in modern patients.
Keywords: central nervous system tumors; external-beam radiotherapy; low-grade glioma; neurosurgery; oligodendroglioma.