The relation of radiological tumor volume response to histological response and outcome in patients with localized Ewing Sarcoma.

Background: Magnetic resonance imaging (MRI) is the modality of choice for local staging and response evaluation of Ewing sarcoma (EwS). Aim of this study was to determine the relevance of tumor volume response (TVR) in relation to histological response (HisRes) and survival, in order to evaluate if early modification of chemotherapy might be indicated in patients with inadequate TVR.

Methods: Three dimensional (3D)-tumor volume data at diagnosis, during early induction phase (1-3 courses of chemotherapy; n = 195) and/or late induction phase (4-6 courses; n = 175) from 241 localized patients were retrospectively analyzed.