Prevalence of asymptomatic brain metastases in metastatic nonsquamous nonsmall cell lung cancer: Treatment implications for resource-constrained settings.

BACKGROUND: Brain metastases (BM) are common in metastatic nonsmall cell lung cancer (NSCLC). However, routine neuroimaging in asymptomatic patients with metastatic NSCLC is controversial as there is no conclusive evidence of benefit from the detection and treatment of asymptomatic BM. Herein, we evaluated the prevalence of asymptomatic BM and its treatment implications in a resource-limited setting.

METHODS: Consecutive patients with newly diagnosed, treatment-naïve, metastatic, nonsquamous NSCLC (NS-NSCLC) were included. Subjects who already had clinical or radiological features suggestive of BM were excluded from the study. All eligible subjects underwent contrast-enhanced magnetic resonance imaging (MRI) of the brain. Management of the detected BM was at the discretion of the treating clinicians.

RESULTS: Among 809 subjects who were screened, 100 (12.4%) were included in the study and underwent MRI. BM was present in 30 (30%) of the subjects and absent in the remaining 70 subjects. A majority of BM were multiple (70%), involved the frontal lobe commonly (73.3%), and had a mean (standard deviation) size of 13.2 (7.3) mm. Detection of BM resulted in a treatment alteration in 17 (17%) of the study subjects (brain irradiation, n = 17, change in targeted therapy, n = 3) with BM. There was no difference in survival of patients who underwent treatment alteration for management of BM compared to those who did not (P = 0.132).

CONCLUSIONS: About one-third of patients with metastatic NS-NSCLC had BM in MRI despite the absence of symptoms. Despite treatment of the majority of the patients with BM with brain irradiation, there was no demonstrable survival benefit. Hence, we conclude that although routine neuroimaging of asymptomatic patients with newly diagnosed metastatic NSCLC may result in treatment alteration (primarily brain irradiation) in a small proportion of patients, it may not influence outcomes in resource-constrained settings.