The prognostic effect of metastasis patterns on overall survival in organ metastatic lung adenocarcinoma

The effect of various metastases patterns on the prognosis of lung adenocarcinoma (AD) remains unknown. The purpose of our retrospective study is to determine whether various metastases patterns have a prognostic impact on patients with organ metastatic lung AD. Patient data was extracted from the Surveillance, Epidemiology, and End Results (SEER) database. The Kaplan-Meier method was chosen for the evaluation of overall survival (OS) rate. Univariable and multivariable Cox regression analyses were conducted to evaluate independent prognostic factors. In the SEER database, 12,228 patients with IV lung AD were retrieved in total. And 78.78% of those patients (9633/12,228) suffered from one of brain, lung, liver or bone metastasis due to disease progression. It was found that the most common site in patients with metastatic lung AD was brain (21.20%), and the least common site of metastasis was liver (3.50%). Patients who suffered single lung metastatic showed relatively good OS, and the median survival time was 11 months (95% CI 0.470-0.516). For those with 2 metastatic sites, data analysis suggested that the median survival times of patients with bone and lung metastasis (10 months; 95% CI 0.469-0.542) were better than others. For those with 3 metastatic sites, data analysis suggested that metastatic pattern had no effect on the OS. Brain is the most common single metastasis site of lung AD. Compared with the other 3 metastatic sites, patients with lung metastasis had better survival results. Deeper knowledge of metastatic patterns will help doctors to better understand the prognosis and formulate more appropriate treatment plans.