OUTCOME OF TREATMENT OF OSTEOSARCOMA IN SURGERY DEPARTMENT, K2 TAM HIEP HOSPITAL A descriptive restropective and prospective and longitudinal follow-up study was conduted on 71 case of bone sarcoma at stage I and II of the bone extremities who were done surgical treatment combined chemotherapy at Hospital K2 Tamhiep from 6/2008 - 6/2014.