What is the average 5 year survival rate for myxofibrosarcoma?

I was diagnosed with A.L.L. (Acute Lymphoblastic Leukemia) in September of 2005 and have been in remission for about 4 years now. A few months ago, my mother was diagnosed with myxofibrosarcoma. She underwent radiation therapy and had the tumor removed; but apparently myxofibrosarcoma comes back fairly frequently. I've looked all over the internet, but I can't find an accurate 5 year prognosis. Please, if anyone has any information on this disease, answer this question. Also, if you can include the rates for the differing grades of this cancer, please do so. Thank you very deeply for your help to all who answer this question respectfully.