Dr.Abreha, Aynalem(Internist,consultant clinical oncologist, assistant professor of medicine, AAU, CHS)Dr.Seife, Edom(Consultant clinical oncologist, assistant professor, AAU, CHS)Worku, Yasin2021-06-202023-11-052021-06-202023-11-052021-03http://etd.aau.edu.et/handle/123456789/26919Background: Primary malignant tumors of bone are extremely rare neoplasms accounting for <0.2% of all cancers, although the true incidence is difficult to determine due to the rarity of those tumors. Bones Sarcomas occur throughout the musculoskeletal system. Osteosarcoma is the most common malignant bone tumor. Osteosarcomas are more common in the appendicular skeleton. Most patients with osteosarcoma have an advanced disease at presentation and the survival is generally poor in low income countries despite the 5-year survival rate of about 80% in the developed countries. Objective: The objective of this study is to describe the clinical features, treatment pattern, and two year overall survival of patients with osteosar coma admitted at TikurAnbessa Specialized Hospital oncology ward. Methodology: A cross-sectional study design was used and all patients with a diagnosis of osteosarcoma admitted to oncology ward were included. A descriptive analysis and frequency were used to analyze mean, median, standard deviation and range. Kaplan Meier was used to analyze the survival pattern of patients. Bivariate and multivariate Cox regression was used to analyze association between dependent and independent variables. Multicolinearity test was done on independent variables found to have association with the outcome variable (VIF>10). STATA software version 16.0 was used for statistical analysis. Result: From 80 patients included in our study, the age ranged between 11 and 58 years with a median age of 19.5 years. Ostoesarcoma peaks between 15-19 years of age. From all patients, 93.75% came after 3 months of the onset of symptoms. Thirty-four patients (42.5%) had documented distant metastasis at presentation. Of all patients with extremity tumors that had surgery, 43 patients (95.5%) had an amputation. Seventy-one patients received chemotherapy, 37 patients (52.11%) received a palliative intent, 18 patients (25.35%) got adjuvant intent, and 16 patients (22.4%) neoadjuvant intent. The median overall survival of osteosarcoma was 20.8  2.96 months (95% CI, 14-50-33.63) and 2-year overall survival was 45%. Conclusion/recommendation: Most patients are delayed at presentation and have an advanced disease. Patients with osteosarcoma were under investigated and received suboptimal care. Patients with osteosarcoma had low median and two-year overall survival. Overall survival was found to be significantly associated with curative surgery (p=0.001), distant metastasis at presentation (p=0.004) and not taking chemotherapy (p=0.05) on bivariate Cox regression but the intent of chemotherapy was the only significantly associated factor for overall survival (p=0.005) on multivariate Cox regression.en-USOsteosarcoma, clinical features, treatment pattern, TASH, EthiopiaThesis