Early stage non-small cell lung cancer patients need brain imaging regardless of symptoms

Japanese Lung Cancer Society and ESMO guideline recommends screening for brain metastasis in all patients with non-small cell lung cancer (NSCLC), while NCCN/ACCP guidelines do not recommend screening patients who are asymptomatic and with clinical stage I NSCLC. However, brain metastasis sometimes occurs in early stage NSCLC patients without any neurological symptoms. We retrospectively reviewed medical records of 124 patients admitted to the University of Tokyo Hospital with stage IV NSCLC from January 2012 to April 2016. We analyzed clinical stage, the presence of the central nervous system manifestations and the number of brain metastases. Forty-six out of 124 cases had brain metastasis at presentation. The brain metastasis group had larger number of female, never smokers and patients with EGFR mutation compared with extracranial metastasis group. Twenty-one of 35 adenocarcinoma cases with brain metastasis had EGFR mutations. Out of 46 brain metastasis patients, 29 patients (63%) were asymptomatic and patients with EGFR mutations were significantly less likely to have neurological symptoms (4/21 vs. 7/14, p = 0.049). Six out of 46 cases with brain metastasis (13%) were clinical T1-2aN0. In clinical T1-2aN0 cases, only one patient had neurological symptoms at presentation. In clinical T1-2aN0 lung cancer patients with brain metastasis, almost all patients were asymptomatic. Patients with EGFR mutations and brain metastasis were likely to be asymptomatic. Regardless of central nervous system symptoms, routine brain imaging seems warranted in all NSCLC patients, especially in areas where patients have a higher frequency of EGFR mutations.