INTRODUCTION The skeletal system is one of the most common distant sites of metastatic non-small cell lung cancer (NSCLC) which may lead to skeletal-related event (SRE). The purpose of this study was to assess the frequency of SRE and the prognostic factors of overall survival (OS) in patients presenting bone metastasis in NSCLC.

METHODS Two hundred and twenty NSCLC patients with skeletal metastases at the time of diagnosis between January 2000 and August 2007 were investigated retrospectively.

RESULTS Forty-seven of 110 patients (43%) without a SRE at the time of diagnosis experienced their first SRE during the follow-up. Patients with squamous cell carcinoma had a 1.8-times higher risk of short OS [95% confidence interval (CI) 1.11-2.84, p=0.016], compared with patients with non-squamous cell carcinoma, and patients treated with EGFR TKIs achieved a 50% protective effect in OS compared with patients not treated with them (95% CI 0.32-0.80, p=0.004). Patients with ECOG performance status 0-1 and single bone metastasis had a 1.8-times (95% CI 1.13-2.60, p=0.003) and 2.4-times (95% CI 1.26-4.46, p=0.008) longer OS than patients with performance status≥2 and two or more bone metastases, respectively.

CONCLUSION Our study demonstrated that the frequency of SRE was common and single bone metastasis, good performance status (ECOG 0, 1), EGFR TKI treatment had good prognosis and histology of squamous cell carcinoma had bad prognosis.