Incidence and predictors of Bone Metastases (BM) and Skeletal-Related Events (SREs) in Small Cell Lung Cancer (SCLC): A Swiss patient cohort

Objectives: Bone metastases (BM) and skeletal-related events (SREs) are frequent complications in patients with lung cancer. Whereas in non-small-cell lung cancer (NSCLC) incidence, prognostic impact, and risk factors are well established, there is only little knowledge in patients with small cell lung cancer (SCLC). We retrospectively evaluated the incidence of BM, SRE and their treatment in a SCLC patient cohort treated at our hospital. We further assessed the role of Lactate Dehydrogenase (LDH), a possible predictor of BM development in SCLC patients. Materials and Methods: We retrospectively analyzed patients with the diagnosis of SCLC for BM, SRE, overall treatment patterns, outcome and established prognostic parameters by record review. The prognostic role of LDH was tested using univariate longitudinal regression analysis. Results: We identified 92 consecutive patients with SCLC diagnosed between 2000 and 2010 at our institution. Overall, 36.9% presented with BM at first diagnosis. Median time to BM from first diagnosis was 14.8 months (range) in limited disease (LD) and 0.9 months (range) in extensive disease (ED). The overall incidence of SRE was 18.4%. Only 19.6% of patients with BM were initially treated with bisphosphonates. Conclusions: Elevated LDH, as well as age ≥75 years were independent predictors for BM development in SCLC patients. Although SREs are relevant complications in SCLC, early antiresorptive treatment of BM to reduce the risk of SREs was rare. LDH served as a predictive factor for BM development in our SCLC cohort and therefore should be taken into account in future randomized controlled trials.