Objective  The progress of anticancer therapy has facilitated the extension of the survival time of advanced tumor patients. However, the incidence of bone metastases and skeletal-related events(SREs) has also increased. This study aimes to analyze the clinical features of metastatic bone tumors for the further improvement of the early diagnosis and treatment of the disease.

  Methods  Clinical data on 408 patients with metastatic bone tumors admitted to Xi'an Chang An Hospital between 2004 and 2011 were reviewed to summarize the medical history, primary tumor, predilection sites, and time of metastasis of the cases.

  Results  Of the 408 patients with bone metastasis, the youngest age of onset occurred in the breast cases(57.68 years), whereas the eldest occurred in the prostate cases(72.33 years). The proportion of the origin of primary tumors was in the following order: lung cancer(55.88%, 228/408), breast cancer(8.58%, 35/408), esophageal cancer(4.66%, 9/408), renal cancer(4.41%, 18/408), liver cancer(2.94%, 12/408), and unknown sites(4.41%, 18/408). The most common metastatic sites were the spine(74.02%, 302/408), ribs(61.27%, 250/408), pelvis(38.24%, 156/408), femur(23.53%, 96/408), and sternum(15.44%, 63/408). The mean time of metastasis was 11.41 months, whereas the shortest and longest times of metastasis occurred in pancreatic cancer(3 months) and breast cancer(55.46 months), respectively. Bone metastasis was found in 276 patients at initial diagnosis. Among the 228 patients with metastatic lung cancer, adenocarcinoma accounted for 39.91%(91/228), squamous cell carcinoma for 24.56%(56/228), small cell carcinoma for 5.26%(12/228), adenosquamous carcinoma for 3.07%(7/228), large cell carcinoma for 0.88%(2/228), and unknown types for 26.32%(60/228). The median survival time was 18.45 months for all 408 patients, and the six-month, the one-year, and two-year survival rates were 61.27%, 27.70%, and 10.29%, respectively.

  Conclusion  Metastatic bone tumors occur the most frequently in patients over 41 years.The most commonly sites of origin include the lungs, breast, esophagus, and kidney. The predilection sites of bone metastases are the spine, ribs, pelvis, femur, and sternum. The thoracic spine is the most common site of vertebral metastases. Lung cancer, renal cancer, and liver cancer are the main cancer types in male patients, whereas the main cancer types for female patients are breast cancer and esophageal cancer. Adenocarcinoma is most commonly found in cases with bone metastases of lung cancer. Comprehensive treatment can significantly control symptoms and can prevent SREs.