Tumor response assessment by modified Choi criteria in localized high-risk soft tissue sarcoma treated with chemotherapy

BACKGROUND. The objective of this study was to compare the prognostic relevance of Response Evaluation Criteria in Solid Tumors (RECIST) versus Choi criteria for the assessment of response in patients with high-risk soft tissue sarcoma of the extremities or trunk wall who received preoperative chemotherapy with or without radiotherapy in a phase 3 trial. METHODS. Patients received 3 cycles of preoperative epirubicin + ifosfamide with or without radiotherapy. The diagnostic concordance between RECIST and Choi criteria and their correlation with overall survival (OS) and freedom from progression (FFP) were evaluated in a univariate Cox regression model. RESULTS. In 243 of 321 eligible patients, RECIST, Choi criteria, and histology were predictive for OS and FFP. In the subgroup of 69 patients who received chemotherapy alone and were evaluable by both RECIST and Choi criteria, Choi criteria were associated significantly with OS and FFP, whereas RECIST predicted only FFP, and the pattern of agreement observed between the 2 criteria was unsatisfactory. On a dichotomous scale, comparing objective response (complete and partial responses) and lack of response (stable and progressive disease) to preoperative chemotherapy according to RECIST and Choi criteria, only Choi criteria were predictive of OS and FFP, and fair agreement between RECIST and Choi criteria was observed. When lack of progression and progression were compared (complete and partial responses + stable disease vs progressive disease), both assessment criteria were significantly predictive of OS and FFP, and there was substantial agreement between the 2 criteria. CONCLUSIONS. Response to chemotherapy with or without radiotherapy was associated with a better outcome in patients with high-risk soft tissue sarcoma. Choi criteria were better predictors than RECIST in patients who received preoperative chemotherapy alone.