Preoperative Imaging in Retroperitoneal Sarcoma

This is a prospective observational study in which patients with untreated retroperitoneal sarcoma will have Magnetic Resonance Imaging (MRI) prior to surgery. In addition, patients who will be undergoing pre-operative radiotherapy will have an additional MRI scan at two weeks post radiotherapy. For both groups, the magnetic resonance images will be correlated with tumour pathology. The study hypothesis is that Magnetic Resonance Imaging will provide a more accurate assessment of tumour volume and local staging than CT and will identify areas of altered oxygenation, cellularity and perfusion which change in response to radiotherapy before tumour shrinkage occurs.