Bone metastases and non-small cell lung cancer: from bisphosphonates to targeted therapy

About 30-40% of patients affected by non-small cell lung cancer (NSCLC) develop, during the course of their disease, bone metastases. The prognosis of these patients is poor with a median survival of less than 1 year. The therapeutic approach includes: palliative radiotherapy, and systemic therapy. In clinical practice, zoledronate is the most commonly used bisphosphonate to prevent, reduce the incidence and delay the onset of skeletal-related events in patients with metastatic NSCLC. However, an Italian Association of Thoracic Oncology (AIOT) survey, conducted to evaluate how bisphosphonates were used in clinical practice for the treatment of lung cancer bone metastases in Italy, showed that the bisphosphonates treatment is still not routine and varies in duration. Denosumab is a fully human monoclonal antibody directed against the receptor activator of nuclear factor kappa-B (RANK)-Ligand inhibiting the maturation of pre-osteoclasts into osteoclasts and is the first example of targeted therapy for bone metastases. An exploratory analysis showed that denosumab was associated with improved overall survival compared with zoledronate in patients with bone metastases from lung cancer. Biochemical markers of bone turnover to predict what patients are at greatest risk of developing skeletal-related events, and to direct treatment of bone metastases with either bisphosphonates or denosumab, are under investigation. This review is focused on the systemic management of bone metastases from NSCLC.