Long-Term Survival in Non-Small Cell Lung Cancer Patients with Metachronous Brain-Only Oligorecurrence Who Underwent Definitive Treatment.

Purpose Metachronous brain-only oligorecurrence in patients with non-small cell lung cancer (NSCLC) is a rare event with favorable prognosis, but the clinical outcome has not been fully determined. We retrospectively analyzed clinical outcomes and prognostic factors in metachronous brain-only oligorecurrence in patients with NSCLC who underwent definitive treatment. Materials and methods We reviewed 4,437 NSCLC patients without oncogenic driver mutations who underwent definitive treatment between 2008 and 2018. Among them, we identified 327 patients who developed 1 to 5 brain metastases with or without systemic metastasis. Of the 327 patients, 71 had metachronous brain-only oligorecurrence without extracranial progression and were treated with local therapy to the brain. Overall survival (OS), progression-free survival (PFS), and prognostic factors affecting OS were analyzed. Results The median OS was 38.9 months (95% CI, 21.8 to 56.1 months) in 71 patients. The 2-year OS rate was 67.8% and the 5-year OS rate was 33.1%. The median PFS was 25.5 months (95% CI, 12.2 to 14.4 months). The longest surviving patient had a survival period of 115 months. Through multivariate analysis, ECOG ≥ 1 (HR: 5.33, p=0.005) was associated with poor survival. There was no significant difference in OS between patients with local therapy and those with local plus systemic therapy (18.5 vs. 34.7 months, p=0.82). Conclusion Metachronous brain-only oligorecurrence NSCLC patients who underwent definitive treatment experienced long-term survival with local therapy, highlighting the unique patient population. The role of systemic chemotherapy in this patient population requires further investigation.