Sarcomas are rare. There are many types and they are difficult to study. The MUHC is known as a major center studying these tumors. We work on curing, diminishing the occurrence of complications and understanding how physical capacities and quality of life are affected. During your different visits, it is possible that you will be asked to participate to different projects, experimental or not. A voluntary participation contributes to the improvement of knowledge and to the development of better care.