Tumor Increase on MRI after Neoadjuvant Treatment is Associated with Greater Pathologic Necrosis and Poor Survival in Patients with Soft Tissue Sarcoma

Purpose: MRI is often used to evaluate sarcoma response to neoadjuvant treatment, however its role to predict for pathologic response and survival is unclear. Methods and materials: From 2003-2010, 116 patients with STS were treated with neoadjuvant therapy (NAT). 62 patients who had an MRI before and after radiotherapy were analyzed. Radiographic change was correlated with survival and necrosis and fibrosis on pathology. ROC curve analysis was used to assess change in volume that best predicted for pathological necrosis. Results: Median follow-up was 33 months. There was median tumor volume decrease of 15.08 cm3 after treatment. Increase in tumor size and volume was associated with greater necrosis (p