Solid subtype predicts early bone metastases in sensitive EGFR-mutated lung adenocarcinoma patients after surgery

This study aimed to explore the prognostic significance of solid pattern for bone metastases (BM) in epidermal growth factor receptor (EGFR)-mutated lung adenocarcinoma patients after surgery. A total of 237 stage I-III lung adenocarcinoma patients with EGFR mutation were analyzed after procedure. The patients were divided into four groups: the solid-present patients with BM, the solid-absent patients with BM, the solid-present patients without BM and the solid-absent patients without BM. The bone disease-free survival (bDFS), systemic disease-free survival (DFS) and overall survival (OS) were assessed. The results revealed that the patients with solid pattern had shorter DFS (15 months vs. 19 months; P < 0.001) and OS (47 months vs. 77 months; P = 0.001). Moreover, bDFS of solid-present patients was significantly shorter than solid-absent patients (27 months vs. 14 months; P < 0.001). In addition, patients with solid component had worsened bDFS, no matter with BM as first-site development (12.5 months vs. 16.5 months; P = 0.016) or non-first-site development (16.5 months vs. 45.5 months; P < 0.001). These findings suggested that solid pattern predicted worse DFS and OS and also showed shortened interval between surgery and BM.