The Soft Tissue and Bone Sarcoma Group (STBSG) of the EORTC ran a phase II study to assess the therapeutic activity of high-dose ifosfamide in patients with advanced soft tissue sarcomas by means of response rate (RR). Investigators claiming a response submitted the relevant chest radiographs (CXR) or scans to two other members of the STBSG for peer review. The reviewers completed a questionnaire indicating overall response or reasons for rejecting the claimed responses. An independent radiologist also reviewed the cases and he was blinded to the results of the peer review until the study was concluded. Twenty-two patients were reviewed by the radiologist and peer review, and the completed questionnaires were retrospectively reviewed. Two differences were noted, one partial responder (PR) was regarded as stable disease by the radiologist and one PR by peer review was determined a complete response by the radiologist. The radiologist found subsequent evidence of progressive disease in three patients who initially showed a PR, whilst the review group noted only one. This study suggests peer review in this tumor type is a satisfactory method of achieving an accurate, objective RR.