Patterns Of Care In The United States Regarding Utilization Of Postoperative Radiation In Low Grade Gliomas

Despite multiple randomized controlled trials, there is no consensus in recommendations for the role and timing of radiotherapy (RT) in the treatment of resected low grade gliomas (LGG). This National Cancer Database (NCDB) analysis evaluated patterns of care and utilization of RT after surgical resection in the United States. The NCDB was queried for patients ≥18 years of age diagnosed with grade 1 or 2 gliomas from 2004-2014 who underwent surgical resection. Patients were categorized as having received post-operative RT (with an inclusive dose range of 45-64.8 Gray [Gy]) or no RT. Multiple logistic regression was performed to assess for demographic, facility-specific, clinical, and treatment associations. A total of 5,428 patients were identified, the majority of whom were of male sex (55.4%) and of white race (88.5%) with the most common histology being astrocytoma (46.6%). Most patients (75.0%) did not undergo adjuvant RT. Those who did undergo RT received a median dose of 54 Gy. A minority underwent chemotherapy (21.5%). The receipt of RT was independently associated with lower income (<$48,000), increased age (OR, 1.018; 95% CI, 1.010-1.026; p<0.001), astrocytic component histology (OR, 1.720; 95% CI, 1.454 -2.034; p<0.001), tumor size greater than 5 cm (OR, 1.498; 95% CI, 1.253-1.790; p<0.001), and receipt of chemotherapy(OR, 6.579; 95% CI, 5.583-7.753; p<0.001). Patients were less likely to receive RT when treated at an academic facility (OR, 0.575; 95% CI, 0.473-0.697; p<0.001), diagnosed in a later year (OR, 0.972; 95% CI, 0.951-0.994; p=0.014), or lived farther from the treatment facility (OR, 0.997; 95% CI, 0.996-0.998; p<0.001). The findings of this analysis reveal that a minority of patients receive post-operative RT in grade 1 or 2 gliomas in the NCDB. RT utilization in the United States appears to be driven both by validated high-risk clinical factors (age, tumor size, astrocytic component) and non-clinical factors (income, facility type, and distance).