Evaluation Of Early Response By Anatomic Imaging To Predict Survival Among Patients With Group Iii Rhabdomyosarcoma: A Report From The Children'S Oncology Group

10012 Background: The prognostic significance of response to induction therapy for rhabdomyosarcoma (RMS) by anatomic imaging (computerized tomographic [CT] or magnetic resonance imaging [MRI] scan) is controversial. We previously reported no relationship between early response and failure-free survival (FFS) for patients on IRS-IV. We repeated the same analysis using an independent cohort of patients with non-metastatic, initially unresected RMS treated on a more recent clinical trial. Methods: A total of 338 patients enrolled in Children’s Oncology Group study D9803 met the following inclusion criteria for this analysis: 1) non-metastatic, initially unresected (Group III); 2) embryonal (ERMS) or alveolar (ARMS) histology; 3) documented response to induction chemotherapy (excluding progressive disease) based on anatomic imaging; and 4) documented therapy beyond week 12. Response at week 12 was determined by the treating institution as complete response (CR, complete resolution), partial response (PR, dec...