P11.29.B Risk factors associated with the presence of brain metastasis at the moment of diagnosis in non-small cell lung cancer patients. Retrospective case series

Abstract

Background Lung cancer is the second most frequent neoplasm worldwide and the leading cause of cancer death in both sexes. Furthermore, it is the most common origin of brain metastases. The aim of this study is to identify clinical, histological, and molecular variables associated with a higher risk of presenting brain metastases at the moment of diagnosis in patients with lung cancer. Material and Methods A single-center retrospective case series analysis of patients with a new diagnosis of lung cancer (from January 2015 to December 2018) was performed. A total of 723 total patients with a new diagnosis of non-small cell lung cancer (NSCLC) were identified. Only patients with a brain imaging study at the time of diagnosis were included in the analysis. Non-parametric statistical tests were used to compare patients with or without metastases at the moment of diagnosis. A uni- and multivariate analysis were performed to identify risk factors associated with the presence of brain metastases at NSCLC diagnosis. Statistical significance was considered when p<0.05. Results We included 135 patients with a new diagnosis of lung cancer and with brain imaging study at the time of diagnosis (mean age at diagnosis of 64.69 years [SD= 10.34]; 71.9% men). The most common histology was adenocarcinoma (67.1%) followed by squamous carcinoma (25.2%). Brain metastases were present in 40% of patients at diagnosis. No significant differences in clinical, histological and molecular variables was identified between patients with or without brain metastases. In any case, as expected, the survival analysis showed that brain metastasis at diagnosis was associated with a worse overall survival (Log-Rank test, p<0.01).The univariate analysis showed that presenting neurological symptoms (OR=19.5, p<0.0001 CI [7.895-47.65]), histology of adenocarcinoma (OR= 2.113, p<0.014 CI [1.160-3.849]) and the presence of visceral metastases (OR= 14.444, p<0.0001 CI [6.161-33.86]) were associated to the presence of brain metastases at diagnosis. The presence of metastases limited to the thorax (OR= 0.019, p<0.001 CI [0.003-0.146] was associated to be free of brain metastasis at NSCLC diagnosis. However, only neurological symptoms (OR= 20.290, p<0.0001 CI [4.953-83.118]), presenting visceral metastases (OR= 4.451, p<0.010 CI [1.458-13.777]) and/or metastases limited to the thorax (OR= 0.066, p<0.024 CI [0.006-0.010]) reached statistical significance in the multivariate analysis. Conclusion Neurological symptoms and the presence of visceral metastases are independent predictors or presenting brain metastasis at the moment of diagnosis in lung cancer patients. On the other hand, the presence of lung cancer disease confined in the thoracic cavity is associated with a lower risk to present brain metastasis