Heterogeneity in intracranial relapses after complete resection of lung adenocarcinoma: Distinct features of brain‐only relapse versus synchronous extracranial relapse

BACKGROUND: Patients with brain oligometastases have better prognosis than those with synchronous extracranial metastases in non‐small cell lung cancer (NSCLC). However, studies focusing on intracranial‐only recurrence after curative surgery remained scarce. This study aimed to explore distinct features of patients with exclusive brain relapse after resection of lung adenocarcinoma. METHODS: Records were retrospectively reviewed of 2809 patients who had complete resection and pathologically confirmed stage IB‐IIIA NSCLC in our hospital from October 2012 to September 2019. Patients were enrolled if they were adenocarcinoma and developed intracranial recurrence thereafter. They were divided into two groups depending on whether they had synchronous extracranial metastases. Clinical and pathological features of patients enrolled were collected and compared between groups. RESULTS: Ninety‐seven lung adenocarcinoma patients with intracranial recurrences were enrolled. The median follow‐up time was 40 months. Fifty patients (51.5%) had brain oligometastases and 47 patients had synchronous extracranial metastases (ECM). Multivariate logistic regression suggested EGFR‐sensitive mutation and male sex were positively correlated to brain‐only recurrence (OR = 2.59, 95%CI 1.04–6.84 and OR = 2.58, 95% CI 1.05–6.75), while higher clinical stage was associated with synchronous ECM (stage II (OR = 0.33, 95%CI 0.09–1.14) or stage IIIA (OR = 0.54, 95%CI 0.20–1.38) versus stage I). No other pathological feature (lymphovascular invasion, visceral pleural invasion, low tumor differentiation, etc.) or adjuvant chemotherapy was associated with intracranial‐only relapse after complete resection of primary tumor. CONCLUSION: Among patients with brain relapse after resection of lung adenocarcinoma, patients with EGFR mutations might have intracranial relapse only without synchronous extracranial metastases. Further prospective studies are warranted to verify this.