Bone metastases in patients with small cell lung carcinoma: rate of development, early versus late onset, modality of treatment, and their impact on survival. A single-institution retrospective cohort study

The aim of the present study was to further explore the impact of bone metastases (BMs) and their therapeutic management on the overall prognosis of patients with small cell lung carcinoma (SCLC). We performed a retrospective analysis of medical records of 363 patients with histologically or cytologically confirmed SCLC, diagnosed and treated in the Oncology Unit of Sotiria Athens General Hospital, between January 2003 and December 2012. Demographic and clinicopathological features, including BMs, their time point of development (early onset/at diagnosis versus late onset/at a subsequent time point), treatment modality for BMs (radiotherapy, bisphosphonates or both) and the presence of skeletal-related events (SREs), were correlated with overall survival (OS). Survival analysis was performed using the Kaplan–Meier method, log-rank tests and Cox regression analysis. Overall, 130/363 patients (35.8 %) were diagnosed with either early-onset (97/363 cases, 26.7 %) or late-onset BMs (33/363 cases, 9.1 %). Patients with early-onset BMs had a reduced OS as compared to those with late-onset BMs [Hazard ratio (HR) 0.61; 95 % Confidence interval (CI) 0.41–0.91; p = 0.015) or those without BMs (HR 0.76; 95 % CI 0.6–0.96; p = 0.024). SREs and treatment modality of BMs had no impact on OS. Multiple Cox regression analysis showed that increased age, poor performance status (PS), presence of BMs and early onset BMs were independently associated with reduced OS. The results of our single-institution study suggest that the development of early-onset BMs may represent an independent predictor of a worse prognosis among patients with SCLC, in addition to well-established adverse prognostic factors such as poor PS.