Randomized phase II study of zoledronate dosing every four versus eight weeks in patients with bone metastasis from lung cancer (Hanshin Cancer Group0312)

•Patients with bone metastases from lung cancer.•4 mg of zoledronate every four weeks (4wk-ZA) or every eight weeks (8wk-ZA).•Primary endpoint; time to first skeletal related event (SRE), its rate and types.•SREs; pathologic bone fracture, bone radiation or surgery, spinal cord compression.•ZA every eight weeks did not result in an increased risk of SREs over one year.