Pulmonary Resectable Metastases of Osteosarcoma With Anti-angiogenics and CHemotherapy

Apatinib 250mg tablet by mouth, bid. 48 hrs break before and 96 hrs after the surgical resection of the pulmonary metastases.

"One cycle: gemcitabine 900 mg/m\^2 over 90 min on Day 1, and gemcitabine 900 mg/m\^2 and docetaxel 75 mg/m\^2 on Day 8. Every 21 days were eligible.~1\~2 -week break before and 2-week break after the surgical resection of the pulmonary metastases is taken."