Factors influencing survival after recurrence in osteosarcoma: A report from the Children's Oncology Group.

Background: Despite drastic improvement in overall survival for pediatric patients with cancer, those with osteosarcoma have stable rates of survival since the 1980s. This project evaluates the effect of several variables on survival after first recurrence in patients with osteosarcoma.

Methods: Data from three prospective North American cooperative group trials for newly diagnosed osteosarcoma are included: INT-0133, POG-9754, and AOST0121. The analytic population for this study is all enrolled patients with first event-free survival (EFS) event of relapse. The primary outcome measure for this retrospective analysis was survival after recurrence (SAR).

Results: The analytic population consisted of N = 431 patients. SAR was statistically significantly associated with age at enrollment (<10 years, P = 0.027), presence of metastatic disease at diagnosis (localized, P < 0.0001), site of relapse (combination lung + bone, unfavorable, P = 0.005), and time to first relapse (2+ years, favorable, P < 0.0001) in multivariate analysis. Ethnicity, primary site of tumor, race, and sex were not significantly related to SAR.

Conclusions: Prolonged SAR in patients with relapsed osteosarcoma is associated with age, extent of disease at diagnosis, site of and time to relapse. Adolescent and young adult patients with osteosarcoma have shorter SAR than younger patients, consistent with studies showing decreased overall survival in this group. Although patients with primary metastatic disease have shorter SAR, there is a subset of patients who relapse greater than 2 years from initial diagnosis that will become survivors. Histological response was significantly associated with time to relapse, but was not predictive of SAR.