Local recurrence has only a small effect on survival in high-risk extremity osteosarcoma.

<bold>Background: </bold>Tumor enlargement after chemotherapy is considered one of the high-risk factors for local recurrence and survival in osteosarcoma. We hypothesized patients with this risk factor will have similar survival regardless of the development of local recurrence.<bold>Questions/purposes: </bold>We asked (1) the prognostic factors for survival in our cohort, (2) how much effect local recurrence has on survival among patients with similar preoperative risk factors, and (3) what prognostic factors are important for survival in these selected patients.<bold>Methods: </bold>We analyzed the prognostic factors for survival in 449 patients with extremity osteosarcoma without metastatic disease at initial diagnosis and treatment (38 with local recurrence, 411 without local recurrence). We compared the survival difference between patients with local recurrence (n = 38) and without local recurrence (control, n = 76) matched for age, location, initial tumor volume, and tumor volume change after chemotherapy, and assessed prognostic factors in this subgroup.<bold>Results: </bold>In a cohort study, multivariate analysis revealed initial tumor volume, tumor enlargement, inadequate margin, and local recurrence predicted poor survival. In the case-control study, the 10-year metastasis-free survival rates of two groups were 13.1 ± 10.7% and 19.3 ± 9%, respectively. In the case-controlled groups, tumor enlargement and initial tumor volume showed multivariate significance.<bold>Conclusions: </bold>Local recurrence has a small impact on survival in patients with high-risk osteosarcoma.<bold>Level Of Evidence: </bold>Level III, prognostic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]