Chemotherapy in head and neck osteosarcoma: Adjuvant chemotherapy improves overall survival

Background: Osteosarcoma is an aggressive bone malignancy presenting uncommonly in head and neck sites. Surgery is mainstay in treatment. However; trials show an improved survival with addition of chemotherapy in the treatment of extremity osteosarcoma. The head and neck osteosarcomas(HNOs) were excluded in these trials because of atypical presentation and disease course. Further; sufficient numbers were not possible for a trial. We present the largest retrospective study from single institute investigating the role of chemotherapy in the management of HNOs. Patients and methods: The retrospective cohort of HNOs treated from 2007 to 2015 of a tertiary hospital were charted. The therapeutic and prognostic factors were analyzed for overall survival(OS), disease free survival (DFS), local control(LC) and metastasis(MT) in univariate and multivariate analysis. The minimum and median period of follow up was 12 months and 56.04 months respectively. Results: There was a total of 157 patients definitively treated with surgery in the time period. 7 patients had positive margins and all were maxillary or skull base tumors. The multivariate cox regression showed significance of tumor site(p = 0.034), margin status (p = 0.006), chemotherapy(p = 0.025), histological subtype (p = 0.012) as predictors of overall survival. The margin status(p = 0.002), Radiotherapy(p = 0.005) were significant predictors for local recurrence. The age and histology subtype(p = 0.058) were borderline significant predictors of metastasis(p = 0.065). The KM method for OS of different chemotherapy groups(p = 0.013), and survival with and without chemotherapy(p = 0.007) was significant. The OS was significantly better with adjuvant chemotherapy among various treatment plans(p = 0.034). Conclusion: Adjuvant chemotherapy improved OS while adjuvant radiotherapy improved local control of HNOs.