CHEMOTHERAPY-INDUCED TUMOR NECROSIS AS A PROGNOSTIC FACTOR IN LOCALIZED EWINGS-SARCOMA OF THE EXTREMITIES

Purpose: This study was performed to assess the prognostic value of th e proposed histopathologic method to evaluate the response of the prim ary tumor to preoperative chemotherapy in Ewing's sarcoma. Patients an d Methods: The response to chemotherapy was evaluated from the specime ns of 118 Ewing's sarcoma patients, who were preoperatively treated by chemotherapy alone. Responses were graded I to III (macroscopic viabl e tumor, microscopic viable tumor, and no viable tumor cells, respecti vely). Follow-up data were available for all patients, with a mean fol low-up duration of 86 months (range, 30 to 158). Results: A statistica lly highly significant difference was observed in outcome among the th ree groups of patients. For patients with total necrosis (grade III re sponse), the estimated 5-year disease-free survival rare was 95%, in c ontrast to 68% for grade II responders and 34% for grade III responder s (P < .0001). This difference was also confirmed when any single grou p was compared with the other groups. Among the parameters rested, pat ient age and the size of tumor had some prognostic value. Conclusion: The proposed histopathologic grading, to evaluate the effect of chemot herapy on the primary tumor, had the strongest correlation to clinical outcome. This method could therefore be used to identify patients wit h a high risk of recurrent disease. These patients could be randomized to receive alternative postoperative treatments to investigate whethe r more aggressive therapies will improve outcome. (C) 1997 by American Society of Clinical Oncology.