Because the combination of sunitinib and radiotherapy has not been studied before, we propose a phase Ib design with dose reductions in the event of excessive toxicity. Sunitinib treatment will precede the commencement of radiotherapy by 2 weeks because there is preclinical evidence that priming the tumor vasculature may increase synergy with radiotherapy, and because sunitinib may have single agent activity in sarcomas, including measurable effects on tumor vasculature. Because it is anticipated that the likelihood of complications attributable to the combination of sunitinib and radiotherapy will be small, the starting dose of sunitinib will be 50mg/day for the two week lead-in period and then 25mg for 5 weeks with concurrent radiotherapy.