Prognostic Factors and Skeletal-Related Events in Patients with Small Cell Lung Cancer with Bone Metastases at the Time of Diagnosis

Background/Objective: The aim of this study was to evaluate the characteristics and prognostic factors of small cell lung cancer (SCLC) with bone metastases. We also investigated the characteristics and predictive factors of skeletal-related events (SREs) in these patients. Materials and Methods: Sixty-one patients who were first diagnosed with SCLC with bone metastases at our institution were included in this retrospective analysis. Results: The overall survival (OS) of patients with bone metastases was shorter than that of patients without bone metastases (4.13 vs. 6.17 months, p = 0.015). Poor Eastern Cooperative Oncology Group (ECOG) performance status (PS; ≥2) and higher serum alkaline phosphatase (ALP; above upper normal limit × 2) were independent poor prognostic factors (p = 0.027 for ECOG PS, p = 0.002 for ALP). More than 1 SRE occurred in 21 patients (34.4%). Cervical spine metastasis, thoracic spine metastasis, pelvic bone metastasis, more than 5 bone metastatic regions and higher serum lactate dehydrogenase were correlated with the occurrence of SREs. Thoracic spinal metastasis was a strong predictive factor for the occurrence of SREs (odds ratio = 5.475; 95% CI: 1.080-27.755). Conclusion: Our study demonstrates the poor prognosis of SCLC patients with bone metastases. Physicians should treat SCLC patients with bone metastases with caution.