poor survival for osteosarcoma of the pelvis a report from the childrens oncology group background the pelvis is an infrequent site of osteosarcoma and treatment requires surgery plus systemic chemotherapy poor survival has been reported but has not been confirmed previously by the childrens oncology group cog in addition survival of patients with pelvic osteosarcomas has not been compared directly with that of patients with nonpelvic disease treated on the same clinical trialsquestionspurposes first we assessed the eventfree efs and overall survival os of patients with pelvic osteosarcoma treated on cog clinical trials we then asked whether patient survival compared with that of patients treated on the same clinical trials with nonpelvic disease finally we asked whether patients with metastatic disease at initial diagnosis had worse survivalmethods we retrospectively reviewed data from 1054 patients with osteosarcoma treated in four studies between 1993 and 2005 twentysix of the 1054 patients 25 had a primary tumor of the pelvis at diagnosis nine patients had metastatic disease the minimum followup was 2 months mean 34 months range 2102 monthsresults two of the nine patients with metastatic disease at diagnosis and five of the 17 with localized disease were alive at last contact estimates of the 5year efs for localized versus metastatic disease of the pelvis were 22 versus 23 os for patients with localized versus metastatic disease was 47 versus 22 patients with osteosarcoma in all other locations had a 5year efs of 57 and os of 69conclusions our analysis confirms poor survival for patients with pelvic osteosarcoma survival with metastatic disease in the absence of a pelvic primary tumor is similar to that for localized or metastatic pelvic osteosarcoma improved surgical or medical therapy is needed and patients with pelvic osteosarcoma may warrant alternate or experimental therapy