Abstract
BACKGROUND: Bone metastasis (BM) is a frequent complication in patients with advanced lung cancer and it causes skeletal-related events (SREs). Our study aim is to prospectively investigate the incidence of BM, incidence and types of SRE, and predictive factors of BM and SREs. METHODS: Newly diagnosed, advanced non-small-cell lung cancer (NSCLC) or small-cell lung cancer (SCLC) patients were enrolled into the study. Patients were followed up every 4 weeks to monitor the development of SREs. Treatment for lung cancer was performed at the discretion of the investigator. RESULTS: Two hundred seventy-four patients were enrolled in this study between April 2007 and December 2009 from 12 institutions. Patients included 77 cases of SCLC and 197 of NSCLC (stage IIIB/IV = 73/124). Median follow-up time was 13.8 months. The incidence of BM at initial diagnosis was 48% in stage IV NSCLC and 40% in extensive stage (ED)-SCLC. Forty-five percent of patients who developed BM had SREs consisting of pathologic fracture (4.7%), radiation to bone (15.3%), spinal cord compression (1.1%), and hypercalcemia (2.2%). Multivariate analysis revealed that factors predicting BM are stage IV, performance status 1 or greater and higher bone alkaline phosphatase in NSCLC patients, higher lactate dehydrogenase, and lower parathyroid hormone-related peptide in SCLC patients. Factors predicting SREs were stage IV, age 64 or younger, and lower albumin in NSCLC patients. Multivariate analysis of SRE was not performed for SCLC because of the small number of events. CONCLUSION: Predictive factors should be taken into consideration in future randomized studies evaluating BM and SREs.