Figure 2. Kaplan-Meier analysis (log-rank test) for organ-specific metastasis in patients with stage I lung adenocarcinoma.

(A) For brain metastasis, the patients were divided into two groups according to number of positive risk predictors (micropapillary subtype predominant and angiolymphatic invasion): none positive or one positive (group 1) (n = 541), and two positive (group 2) (n = 15). Patients with both micropapillary subtype predominant and angiolymphatic invasion had significantly worse brain metastasis-free survival than others (P < 0.001). (B) For liver metastasis, the patients were divided into two groups according to number of positive risk predictors (solid subtype predominant and angiolymphatic invasion): none positive or one positive (group 1) (n = 540), and two positive (group 2) (n = 16). Patients with both solid subtype predominant and angiolymphatic invasion had significantly worse liver metastasis-free survival than others (P < 0.001).