Abstract: Objective: To determine the prognostic factors of primary osteosarcoma in adults. Methods: This is a review of 54 patients older than 40 years (24 men and 30 women) who were treated between 1998 and 2011 at the authors’ institution. Demographic information and follow-up data were obtained and statistically analyzed. Results: Tumors involved the limbs in 30 patients (55.5%) and axial skeleton in 17 patients (31.5%), and arose from soft tissue in 7 patients (13%). And 6 patients (11.1%) had synchronous metastasis. According to our review, tumors were treated surgically in 52 patients (96.3%). Local recurrence was documented in 14 patients (26.9%). Metastasis after diagnosis appeared in 21 patients (38.9%). In the 52 patients who received the surgical treatment, the 5 year disease-free survival and overall survival rates were 43.7% and 50.4%, respectively. Conclusion: Adult patients with primary osteosarcoma had a poor clinical outcome. Inadequate surgical margins, more tumors in the axial location due to high recurrence rates, metastatic disease at presentation, and large tumor volumes were associated with significantly lower survival rates. Aggressive multi-agent treatment regimens might improve survival.

Key words: Osteosarcoma, Prognosis, Adults, Survival analysis