Hi, Thanks for writing in. Soft tissue sarcoma in the arm is a type of cancer in the muscle. The main treatment of this tumor is surgical excision and this can be followed up by radiation or chemotherapy. This sort of cancer might have a locally aggressive form or might even spread to other areas. It is best to go through your reports of biopsy and MRI scan and then know the extent of the tumor. It will help to know if you have consulted any cancer surgeon and they have done any surgery earlier. Cancer treatment is not easy and in some patients every medicine available might have to be tried before getting a observable cure. Since you have the problem for 8 years and there is no other problem mentioned by you therefore it looks like a locally aggressive disease. I suggest you consult a cancer surgeon at a cancer institute and then discuss treatment options available depending on your disease extent and past treatment details. Wish you a quick recovery.