Use of brain radiotherapy as part of first course of treatment for NSCLC with de novo brain metastasis.

Abstract

9118 Background: Loco-regional management of brain metastases from non-small cell lung cancer (NSCLC) are surgery and/or brain radiotherapy, either whole brain (WBRT) or stereotactic (SRS). We used a national registry to evaluate trends in the use of brain radiotherapy as part of the first course of management in patients diagnosed with de novo brain metastasis. Methods: We retrospectively analyzed the National Cancer Database (NCDB) to identify patients with NSCLC and de novo brain metastasis diagnosed from 2004-2016. We described the socio-demographic and clinical characteristics of this population, then used chi-squared testing to evaluate for an association between these variables and the use of brain radiotherapy (either SRS or WBRT). Significant variables (p < 0.05) were included in a multiple logistic regression model. Results: Of n = 41,454 patients with NSCLC and de novo brain metastasis, n = 27,949 (67.4%) received either SRS or WBRT as part of their first course of treatment, while n = 13,505 (32.6%) did not receive primary brain radiation. Of those that did not receive radiation: n = 9,927 (73.5%) were < 70 years old while n = 3,578 (26.5%) were ≥70. N = 11,081 (82.7%) were White, n = 1,550 (11.6%) were Black and n = 768 (5.7%) were Asian. Variables significantly associated with the use of primary brain radiotherapy at the multivariate level were: treatment facility type (p = 0.004), tumor histology (p < 0.001), clinical T-staging (p < 0.001), and clinical N-staging (p < 0.001). Age, sex, race, comorbidity, grade, insurance status, and setting (metro vs. rural vs. urban) were not significantly associated with the use of radiotherapy. Compared to patients treated at community cancer programs (CPs), those treated at comprehensive community CPs (OR 1.152, 95% CI 1.027-1.291, p = 0.015) and academic CPs (OR 1.242, 95% CI 1.104-1.398, p < 0.001) were more likely to receive primary brain radiotherapy. Patients with squamous NSCLC were less likely (OR 0.680, 95% CI 0.619-0.747, p < 0.001) to receive brain radiotherapy compared to those with adenocarcinoma. Finally, patients with advanced T-staging (p < 0.001) and N-staging (p < 0.001) were less likely (OR < 1) to receive brain radiotherapy as part of the first course of treatment. Conclusions: While insurance status and setting were not significantly associated with the use of brain radiotherapy, facility type was. Further research is needed to evaluate whether this is a true disparity in medical practice, or the differences can be explained by characteristics of the patient population undocumented by the NCDB (e.g. severity of brain metastasis). Additionally, patients with larger primary tumors were less likely to receive brain radiation as part of the first course of treatment, which may reflect the need for local therapy prior to treating metastatic sites.