National trends in radiotherapy for brain metastases at time of diagnosis of non-small cell lung cancer.

BACKGROUND: To analyze the national trends of patients treated radiotherapy for brain metastases from non-small cell lung cancer (NSCLC) that were found at diagnosis.
METHODS: The National Cancer Database was queried for patients with NSCLC diagnosed from 2004 to 2013 that received brain irradiation for metastases and patients grouped into having had received fractionated brain radiotherapy (5-15 fractions with or without radiosurgery) or intracranial radiosurgery alone (1-5 fractions). Univariable and multivariable (MVA) analyses were performed to investigate factors associated with the receipt of SRS alone, and temporal/regional trends.
RESULTS: 47,746 patients met inclusion criteria, of which 42,148 received fractionated brain irradiation (88%) and 5,598 received radiosurgery (12%). 345 patients received fractioned brain irradiation with a radiosurgical boost (0.8%). The utilization of radiosurgery-alone increased over time owing to increases in each radiosurgery modality. On MVA, several factors were associated with increased odds of receiving intracranial radiosurgery-alone over fractionated brain radiotherapy including more recent year of diagnosis, increased median income, eastern U.S. regions, further distance to the hospital, and the receipt of chemotherapy (each p<0.001). Patients of Asian descent were less likely to receive radiosurgery alone (p=0.044).
CONCLUSIONS: In the management of brain metastases from NSCLC, overall utilization of an intracranial radiosurgery alone treatment strategy has increased over the past decade. Despite this, there appear to be significant geographic variations and disparities remain based on patient income level and race. Further study is needed to define the reasons for these disparities and appropriate actions to mitigate them.