['In patients with non-small cell lung cancer (NSCLC), the development of liver metastasis (LM) is a poor prognostic factor. Whether systemic treatment combined with local treatment for LM has benefit for NSCLC patients with LM is unknown.', 'We retrospectively reviewed and analyzed the clinical data and tumor epidermal growth factor receptor (EGFR) mutation status of 673 pulmonary adenocarcinoma patients, including 85 patients who developed LM at any time point in the course of the disease. Radiofrequency ablation (RFA) with real-time ultrasonographic guidance was used for local treatment of LM in these patients, if appropriate.', 'Patients with an EGFR mutation were more prone to having synchronous LM than patients with EGFR wild-type (50.0% vs. 23.5%, P=0.019). Fifty-six patients (65.9%) had ≦5 LM nodules. The median overall survival (OS) of patients with ≦5 LM nodules was 7.6 months compared with 2.9 months for those with multiple nodules (P<0.001). The independent prognostic factors after LM were performance status, EGFR mutation, synchronous LM and LM numbers. The independent prognostic factors for patients with ≦5 LM nodules were performance status, EGFR mutation, LM concomitant with adrenal metastasis and having received RFA. Patients who received RFA treatment (n=6) had longer OS after LM than those without RFA treatment (n=42) (23.1 vs. 7.9 months, P=0.035).'] Does number of liver metastatic nodules affect treatment options for pulmonary adenocarcinoma patients with liver metastases?