Brain metastasis from non-small cell lung cancer (NSCLC): Prognostic importance of the number of involved extracranial organs

Background and purpose: This study investigated the potential prognostic value of the number of involved extracranial organs in patients with brain metastasis from non-small cell lung cancer (NSCLC). Material and methods: A total of 472 patients who received whole-brain radiotherapy (WBRT) alone with 5 × 4 Gy or 10 × 3 Gy for brain metastasis from NSCLC were included in this retrospective study. In addition to the number of involved extracranial organs, 6 further potential prognostic factors were investigated including WBRT regimen, age, gender, Karnofsky Performance Score (KPS), number of brain metastases, and the interval from cancer diagnosis to WBRT. Subgroup analyses were performed for patients with metastatic involvement of one (lung vs. bone vs. other metastasis) and two (lung + bone vs. lung + lymph nodes vs. other combinations) extracranial organs. Results: The survival rates at 6 months of the patients with involvement of 0, 1, 2, 3, and ≥ 4 extracranial organs were 52, 27, 17, 4, and 14 %, respectively (p < 0.001). On multivariate analysis, the number of involved extracranial organs remained significant (risk ratio 1.32; 95 % confidence interval 1.19-1.46; p < 0.001). Age < 65 years (p = 0.004), KPS ≥ 70 (p < 0.001), and only 1-3 brain metastases (p = 0.022) were also significantly associated with survival in the multivariate analysis. In the separate analyses of patients with involvement of one and two extracranial organs, survival was not significantly different based on the pattern of extracranial organ involvement. Conclusion: The number of involved extracranial organs is an independent prognostic factor of survival in patients with brain metastasis from NSCLC, irrespective of the pattern of extracranial organ involvement.