Abstract: Background and purpose: Osteosarcoma is a tumor originated from mesenchymal tissue, which often occurs in teenagers. It often occurs in long bones, rarely in maxillofacial regions. The present treatment is mainly in surgery followed by chemotherapy and radiation. It is an infrequent disease and hardly reported. In this study, we compared clinical differences in 32 maxillofacial osteosarcoma patients and identified the prognostic factors in the disease. Methods: The clinical data of 32 osteosarcoma patients were retrospectively reviewed. The data covered the period from Jan. 2010 to Jan. 2017, and included sex, age, tumor site. The mean follow-up time was 75 months (ranging from 7 to 90 months). The Kaplan-Meier method was used to measure the overall survival rate. A log-rank univariate analysis was used to determine the prognostic factors related to the survival rate. The Cox model multivariate analysis was used to identify independent prognostic factors. Results: The median survival time of 32 patients in the present study was (47.6±8.4) months (95%CI: 31.1-64.1). The 1- and 2-year cumulative survival rates were 84% and 72%, respectively. The 5-year cumulative survival rate was 44%. Log-rank univariate analysis showed that the significant factors were size, surgical margin and frequency of adjuvant chemotherapy. Surgical margin and frequency of adjuvant chemotherapy were closely related to recurrence. Cox regression analysis revealed that surgical margin and frequency of adjuvant chemotherapy were the prognostic factors. Conclusions: Maxillofacial osteosarcoma has unique features and prognosis. Surgical margin and frequency of adjuvant chemotherapy were the prognostic factors in osteosarcoma.

Key words: Osteosarcoma, Relapse, Metastasis, Prognostic factors, Survival, Cox proportional hazard model