Prognosis of extremity osteosarcoma in patients aged 40-60 years: a cohort/case controlled study at a single institute.

BACKGROUND: The outcome of older osteosarcoma patients with multi-disciplinary management has not been clearly defined. METHODS: We conducted a cohort (n=375) and a case-control (n=78) study on 26 older age patients (40-60 years) with localized osteosarcoma of extremity. In the case-control study, controls were matched for location and initial tumor volume. RESULTS: Compared to 349 younger patients, older age patients showed an osteolytic pattern on plain radiographs (P=0.05), fibroblastic subtype (P<0.01), and poor histologic response (P=0.03). Multivariate analysis revealed that a large absolute tumor volume (P<0.01), a tumor location in the proximal humerus (P=0.02), and a poor histologic response to preoperative chemotherapy (P<0.01) independently predicted poorer metastasis-free survival. However, an older age showed marginal significance (P=0.09). A case-control study showed a higher proportion of the fibroblastic subtype and poor histologic response in the case group. Five-year metastasis-free survival rates for the 26 cases and 52 controls were 40.1+/-10.1% and 61.5+/-6.8%, respectively (P=0.02). CONCLUSIONS: Older age osteosarcoma patients showed an unfavorable histologic response to chemotherapy and lower survival than younger patients. Nevertheless, a further larger-scale study is required to confirm our observations.